Why do cucumbers curl into a C-shape?
Most cucumbers grow in a straight cylindrical shape. Except when they don’t. Sometimes, a cucumber will curve into a C-shape. This is called cucumber fruit curl. It is also called crooking. There are many causes for crooking. Which one is affecting your fruit?
Some sap-sucking cucumber pests can cause crooking. This form of crooking is usually irregular, having been caused by thrip, mite, and whitefly feeding. Aphids, scale, and mealybugs can also cause this type of deformity.
Cucumbers are heavy feeders. They need nutrient rich soil and regular feeding to produce a healthy crop of uncurled cukes. You can side dress the vines with aged compost. This also acts as a mulch, which helps stabilize soil temperatures and reduces the need for added water.
Think about how much of a cucumber is water. Add the water needs necessary to grow the vines and you will see that cucumbers need a steady supply of water. This means watering regularly and consistently. If you have placed mulch around the vines, add water whenever the top inch of soil feels dry.
Hot weather/incomplete pollination
Hot weather kills pollen. This can mean the female flower did not get enough pollen to produce a properly shaped cucumber. This normally causes stunting or lopsided development, but it can also cause curling.
Newly forming cucumbers are easily pushed around by stems, leaves, and flowers, as well as the ground itself. Also, if the flesh is damaged early on in development, the damaged side may grow more slowly, causing a curled shape.
How to prevent crooking
A curled cucumber is fine to eat.
We’ve all played with sand at some point. There were probably waves crashing in the distance, the smell of tanning lotion and sunscreen mixing with salty air. Sand gets everywhere and it can be used to make some amazing temporary castles and other works of art. It is also a component of soil.
What makes soil?
Soil is a combination of minerals, organic stuff (living and dead), liquids, and gases. The liquids and gasses, mostly air and water, move through large and small spaces called macropores and micropores, respectively. Soil can be mostly clay, mostly silt, mostly sand, or somewhere in between. Clay, silt, and sand classifications are more about particle size than actual material, but here’s the typical breakdown:
[Note: μm stands for micrometer, or micron. One micron equals one one-millionth of a meter.]
Soil texture and nutrient availability
If you live in Florida, you know all too well how difficult it is to keep nutrients and water in your sandy soil. This is because the spaces between the grains of sand are so big. At the other end of the spectrum, clay is made up of flat plates that tend to stick together, holding tightly to water and nutrients and making it difficult for plant roots to move through it. It very few macropores and micropores, which means drainage and aeration are common problems. This is also why it makes such nice pottery.
The Sand-Clay Myth
What is a gardener to do? Our intuition tells us that we can lighten heavy clay soil by adding sand. It sounds right. Sand has plenty of spaces! Putting the two together should give us a nice, happy medium, right? Wrong. Instead, the tiny clay particles fill in all the spaces around the sand grains, creating a soil that is even heavier than before!
Organic mulch to the rescue!
When I say ‘organic mulch’, I am not necessarily saying organic in the OMRI sense, although that is what I use. Organic mulch refers to mulch composed of materials that were or are alive: plants, animals, bugs, manures, that sort of thing. It does not include ground up plastics or other manufactured materials. When you incorporate organic mulch into sandy soil, you provide materials that can bind nutrients and water to the planting bed. The macropores become partially filled with water- and nutrient-retaining compost. When you top dress heavy clay soil with an organic mulch, earthworms, microorganisms, irrigation, and other actions will slowly incorporate chunks of non-clay material below the soil line, creating macropores and micropores for air, water, and plant roots to move through. Top dressing means you just leave the material on top of the soil, rather than digging it in. Digging clay soil is generally not helpful because of the smooth surface left behind by the shovel. When that surface dries, it can be impenetrable.
So, leave the sand at the beach or in your egg timer. If you have clay soil, organic mulch is what you want to use. You may be surprised to learn that sand is a non-renewable resource in high demand, due to our penchant for concrete. Apparently, creating sand take eons and we use a lot of it.
Salvia is tough and beautiful. The bees love it and you probably do, too!
This member of the mint family is one of those no-brainer plants here in the Bay Area. Composing the largest genus of mints, this group of plants includes the culinary favorite, sage (Salvia officinalis). Most ornamental salvias are referred to by their Latin name. The word salvia comes from the Latin word ‘salvere’, which means to feel well and healthy.
Salvias tend to be woody plants, which is one reason why they are so good at handling drought. Depending on the variety, they can be evergreen or deciduous, annual, perennial, or biennial. Like other mints, the stems tend to grow at angles to each other and are square. The flower spikes are the big attraction. They consist of a modified leaf, called a bract, and stalked, clustered flowers, called racemes or panicles. Flowers can be red, pink, yellow, or white, but the deep blueish-purple is my favorite. Hummingbirds, butterflies, and other beneficial pollinators love them, as well.
Weird salvia science
Unlike most mints, which have four stamens, salvia have a unique pollination mechanism that uses only two stamens and connective tissue (thecae) that create a lever action. Within male flowers, this lever action causes pollen to be dumped on any visiting pollinator. After the pollinator leaves, everything returns to its normal position. In female flowers, the same mechanism pushes the stigma to be in the same general area on the pollinator’s body, increasing the likelihood of pollination and fertilization (assuming they are the same size).
How to grow salvia
Salvias can be grown from seeds, seedlings, or cuttings, depending on the variety, once the last frost date has passed. Most salvias prefer full sun and good air circulation. An exception is the Japanese yellow sage (Salvia koyamae), which prefers shade and moist soil. If your soil is heavy clay, like mine, you will want to incorporate some aged compost to lighten it up before planting. Salvias will produce more blooms with regular feeding. You can also mulch around plants with aged compost for reduced moisture loss and slow-release feeding. If you prune your salvias before they bloom, flowering can be significantly delayed. Better to shear your salvias at a time of year when they are not flowering. And be sure to deadhead spent blooms the rest of the year to stimulate more flower production. While being drought tolerant, your salvias will need to be watered. Just wait until you notice some moderate wilting, to avoid common fungal diseases.
Salvia pests and diseases
Rust, powdery mildew, and leaf spot may occur, but they can often be prevented with proper water management [Read: avoid overhead watering]. Aphids and thrips will be the most common pests. [Aren’t they always?] Many salvias have hairs on leaves and stems that discourage many pests and grazers (and my chickens).
Whether you choose edible culinary sage, fragrant pineapple sage (Salvia elegans), the sacred white sage (Salvia apiana), or sturdy purple sage (Salvia dorrii), try adding some salvia to your landscape or garden today!
The heady aroma of summer nectarines and peaches means it’s time to be on the lookout for peach twig borers.
While examining my nectarines for ripeness, I spotted a reddish-brown larva with white bands undulating across a twig. Of course, I picked it up and dropped it in a little plastic bag and sealed it up tight, until I could look it up. That’s what I learned that even the nicest tree cage has its limits.
Peach twig borer description
The reddish brown larva I saw was relatively mature. They hatch out white with a black head. As they feed, the color darkens. Unlike other larval pests of peaches, the peach twig borer has white bands around its abdomen, though the bands are not always as obvious as they are in the photo above. The pupae are 1/4 to 1/2 inch long and brown. They do not have a cocoon. Adult moths are small, slender, and a mottled grey color, with fringed wings and a false snout. Oval eggs are yellowish-orange and laid on fruit, twigs, and leaves.
Peach twig borer control
Tachinid flies and braconid wasps provide natural controls. When that isn’t enough, you can spray environmentally sound insecticides, such as Bacillus thuringiensis (Bt) or spinosad, just as blossoms appear, for added peach twig borer control. Dormant oil can also be used in winter, when combined with the same insecticides, to kill off the overwintering larvae. The oil will not kill peach twig borers by itself. Pheromone traps can be used to interfere with mating and to monitor for these pests. Just be aware that hanging a pheromone trap can actually attract pests to your trees if handled incorrectly. Read the label.
So, as you check your nectarines and peaches for ripeness each summer, be on the lookout for these tiny pests. Also, add preventative treatments to your garden calendar while you’re thinking about it.
The summer song of crickets and grasshoppers provide many of us with a comforting reminder of childhood. If you are a gardener, your might hear those sounds with different ears.
Cousins to katydids and locusts, crickets (Gryllidae) and grasshoppers (Acrididae) are members of the Orthoptera family.
Both crickets and grasshoppers have a large head, long saltatorial* back legs, for jumping, a cylindrical body (pronotum), compound eyes, and a mouth able to bite and chew. They have two pairs of wings: the forewings (tegmina) and hindwings. Beyond those similarities, there are many differences:
Lifecycle of crickets and grasshoppers
Both species start out as eggs that were laid, in late summer and early fall, in the top 2 inches of soil, in clusters of 20 to over 100 eggs. In spring, these eggs hatch as nymphs, which begin feeding on nearby plants. When those food supplies are exhausted, they look for new places to feed, generally downhill from where they started. Grasshoppers will molt 5 or 6 times as they outgrow their exoskeletons, and crickets molt 8 or more times. There is no pupal stage, so these insects are said to go through incomplete metamorphosis.
There are house crickets and field crickets. Both are collective terms for several different cricket species. All of them feed on seeds and plants, along with grasshopper eggs, moth and butterfly pupae, flies, and spider sack lunches. House crickets (Acheta domesticus), sold as lizard food, are usually brown or tan, and one inch long or less. Field crickets are slightly larger than house crickets and they are usually black.
While there are over 200 different types of grasshoppers in California, only two cause significant damage: the valley grasshopper (Oedaleonotus enigma) and the devastating grasshopper (Melanoplus devastator). Most grasshoppers can fly.
Cricket and grasshopper damage
If their song didn’t tell you these pests had arrived, chewed holes in leaves certainly will. Grasshoppers and crickets will often hide out in nearby weeds and brush, so keeping those areas mowed can reduce the likelihood of a visit. On the flip side, maintaining a lush, green border may provide all the feeding that is needed by a few individuals. In any case, a single cricket will not do significant damage, but a large number of them can decimate a row of seedlings in just one night. Grasshoppers prefer green plants, so your lettuce, onions, carrots, corn, beans. melons, squash, and some annual flowers are vulnerable. Grasshoppers may also feed on citrus, avocado, and beets. In years with especially wet springs, cricket and grasshopper populations can explode. In these years, food scarcity makes all plants vulnerable.
Grasshopper and cricket controls
If these insects are causing damage in your garden or landscape, floating row covers, screened boxes, and cones are your best bet. Just be sure there are not any individuals hiding out in the mulch around your plants, or you may create a virtual Club Med for the pest! Birds, robber flies, and blister beetles feed on crickets and grasshoppers, or their eggs, and many parasites, bacteria, and fungi attack these garden pests. You can hand pick them if you are quick enough. Chickens are excellent at catching them, and it’s a riot to watch.
* For you word game and vocabulary nerds, saltatorial is an adjective that describes the legs of jumping insects.
Callus is what plants use instead of bandaids.
What are tree wounds?
Tree wounds can occur on purpose, by pruning, or by accident, from heavy winds or by being overladen with fruit. Most pruning cuts are relatively smooth. Accidental wounds tend to be jagged and the bark may be torn down the trunk. In these cases, the tree will benefit from the branch being cut back to a place where a flat wound is possible. This gets rid of insect hiding places and speeds the healing process for the tree. In both cases, interior tissue is exposed to the elements.
Traditional wound treatment
For decades, people have said that we should protect tree wounds with paint, pastes, and salves, which are generally petroleum based. The idea behind these treatments was that an open wound was vulnerable and that we could ‘help’ our trees by painting the cut surface with tar, asphalt, wound paint, or some other sealant. Instead of providing protection, these treatments actually seal in harmful bacteria and fungi, increasing the chance of disease or decay. Also, there are certain disease-carrying organisms that love to feed on or are otherwise attracted to the sealant!
It ends up, trees already know how to protect themselves. Just as our skin forms a callus in response to hard work and friction, trees create tissue over wounds to protect themselves from pests and diseases. The word ‘callus’ is from the late Middle English Latin word ‘callosus’ which means ‘hard-skinned’. Trees are able to generate their own ‘hard skin’ to cover a wound. If that process is interrupted with oil-based sealants, the internal processes of decay prevention may also be interrupted.
An exception to the rule
One case where wound dressing is a good idea is in regions (like ours) where oak wilt is a problem. If an oak in these areas is damaged or requires pruning, a sealant that contains insecticide and fungicide can prevent loss of the tree.
Why do the flowers keep falling off your tomato, squash, melon, and bean plants, and citrus trees?
This condition is called blossom drop. Blossom drop can be caused by several factors, most of which are perfectly normal. Others, not so much. Generally speaking, unfertilized flowers are kicked to the curb. Here are some species-specific causes of blossom drop.
Citrus June drop
Most citrus trees will produce far more flowers than they could possibly bring to maturity. When the tree decides it has enough fertilized flowers, usually around June, the rest are discarded. It’s nothing to worry about.
Cucurbit blossom drop
The first flowers on your melons, winter or summer squash, and cucumber are generally male. These drop naturally after a brief appearance. If female blossoms start falling off, it is usually because of thrip damage, poor soil fertility, environmental factors, or inadequate pollination. You can attract more bees and other pollinators to your garden by adding yarrow and bee balm. You can also allow onions, carrots, and fennel to go to seed. These plants will all provide pollen and nectar to beneficial insects that should increase pollination rates. If that doesn’t work, you can always try hand-pollinating.
Bean blossom drop
Temperatures over 90°F will cause bean flowers to abort. This can also occur with insufficient irrigation and poor air quality due to smog or fires. If you know your summer temperatures are likely to go over that threshold, try planting beans earlier or later in the season.
Tomato and pepper blossom drop
Tomatoes and peppers often drop their blossoms when environmental conditions are unfavorable. This might mean any of the following:
How to reduce blossom drop
Use these handy tips to reduce blossom drop in your garden:
The good news about blossom drop
Luckily, when environmental conditions cause blossom drop, most plants will simply try again, producing a second crop of blossoms.
Pergolas are more than shade structures.
Shade structures protect us from the sun’s summer glare, but they are often poorly made and generally don’t last more than a season or two. Pergolas, on the other hand, are sturdy structures that can provide shade for decades. Let’s find out why pergolas are such a good idea.
Pergolas reduce the heat sink effect
Many homes have concrete patios. Concrete acts as a heat sink that absorbs and then radiates a phenomenal amount of heat in the summer. This is also known as the urban heat island (UHI) effect. As this heat is radiated, it can cause several problems:
Shade can reduce the ambient temperature by as much as 15°. If it’s 100°F outside, that can make a huge difference in your comfort, your plants’ health, and your cooling bill.
Pergolas as protection
The word ‘pergola’ comes from the Latin word ‘projecting eave’. People have been creating shade for themselves since, well, since there have been people! At first, pergolas provide only marginal protection from the elements. Over time, as climbing plants make their way up and across the top of your pergola, the shade protection can become significant. After many years of growth, your pergola may even offer something of a rain barrier!
A structure by any other name…
Pergolas are spaces defined by upright posts or beams and an open lattice above that is normally used as support for climbing plants. Many people call pergolas by other names: arbors, gazebos, and bowers, but they are technically incorrect. The words describe slightly different versions on a theme, but there are differences:
Pergola: DIY, ready-made, or custom
This decision is one of those time-or-money questions. Most of us have one or the other, but rarely both. If you have time and tools, you can find designs online and at your local library for a wide variety of pergola styles. The building process is relatively straightforward. If you prefer more convenience, there are ready-made pergolas with the lumber already cut and drilled and all you do is assemble the pieces. If you have money to spare, the sky is the limit. You can custom design a pergola to fit your space and style, creating a unique, artistic sanctuary in your garden or landscape.
Plants and pergolas
One of the biggest problems with vine-covered pergolas is weather. [I’m speaking from personal experience here.] One night of freezing temperatures and your trumpet vine, wisteria, or honeysuckle can be killed off, leaving behind a skeleton of its former self. Luckily, in most cases, the root system will be able to recover thanks to that heat-sink concrete patio slab. Of course, covering an 8- or 9-foot high pergola with some square footage takes time. You may want to supplement your shade with shade cloth for the first few years. And if freezing temperatures are predicted, hang some old fashioned Christmas lights, drape plants with fabric (without touching), or fire up the BBQ grill. [Just make sure you don’t start a fire somewhere else!]
Pergola plant selection
As you select plants to grow up your pergola, make sure they are suited to your microclimate in terms of temperature, sun exposure, and soil. This will help your plants thrive and reduce your workload. You should also consider bloom time. Some people install multiple plants with different bloom times and colors for a longer season of flowers. Of course, my personal favorites are the edibles! Here are some popular plants for pergolas:
Training your pergola plants
Most climbing plants, even self-clinging varieties, will benefit from a little help, at first. You can gently tie new stems to the nearest pergola post, leaving the ties in place until the tendrils have taken a firm hold on their own. Once plants have reached the top of the pergola, these ties can be removed.
So, more than just shade, a pergola can provide support structure for climbing plants, reduced water and electric bills, increased home value, and even art!
Bacterial speck may sound redundant - we all know bacteria are tiny - but bacterial speck is a bacterial disease of tomatoes that can be controlled with a speck of good cultural practices.
Bacterial speck looks a lot like bacterial spot and bacterial canker, but it is less likely to be fatal. All three diseases appear as small brown or black lesions on leaves, stems, and fruit. These lesions may merge into larger, irregularly-shaped areas. There is normally a yellow halo around these lesions and the interior tissue dies rather quickly. Most of these lesions are found near leaf edges (margins). On fruit, the lesions look like tiny black bumps.
Bacterial speck lifecycle
Bacterial speck is caused by Pseudomonas syringae pv. tomato, a cousin of the bacteria that cause angular leafspot, citrus blast, and leaf spot. This bacteria is found in soil and on seeds. Seeds from diseased fruits should not be planted the following season, or you will simply continue the process in your garden. These bacterium can remain dormant for a very long time, until the weather turns cool and damp. Then they start growing like crazy. The bacteria are frequently splashed onto leaf surfaces by rain and overhead watering.
Bacterial speck control
Fixed copper sprays and good air circulation are your best preventative measures. You can also delay spring planting until after temperatures warm up, and avoid overhead watering. Properly spacing plants can reduce the spread of infection.
Diseased fruits are safe to eat, simply cut out the infected areas and toss them in the trash (or feed them to your chickens). Diseased plants should not be composted. Instead, toss them in the garbage to reduce the likelihood of reinfection.
Bee balm is a striking North American native that attracts more than just bees to your garden.
Bees and other pollinators are what help your garden plants produce the fruits and vegetables we love. Adding plants that they love can increase your bounty many times over. Bee balm also provides pollen and nectar to other beneficial insects.
Antiseptic bee balm
Bee balm is a perennial. It is also a member of the mint family. Like other mints, bee balm has antiseptic properties. In fact, it is still used as a primary ingredient in popular mouthwashes. Native Americans used bee balm leaves and flowers to treat headaches, wounds, flatulence, and respiratory problems. They also used it to season wild game. While somewhat bitter, it tastes like a combination of peppermint and oregano.
The bee balm plant
Bee balm (Monarda), also known as wild bergamot, horsemint, and Oswego tea, loves sunshine. If it is grown in partial shade, it will stay low to the ground and produce very few flowers. Grown in full sun, it can reach four feet in height, though most are only half that. The flowers, which tend to appear in early to late summer, are striking, with white, pink, and purple tubular daisy-like blooms. You can also find dwarf varieties that look lovely in containers.
How to grow bee balm
Bee balm, like other mints, prefers rich, moist soil. If enough moisture is present, bee balm can overtake an area. Some varieties can tolerate more dryness than others, so do your homework. It is easiest to buy bee balm plants from a reputable seller, or, if you know someone with an established plant, you can ask them to share some with you the next time they are dividing their plants. Bee balm can be planted in spring or fall. Plants should be spaced two feet apart, and the planting hole should have some compost worked into it, to a depth of 12 to 15 inches.
In most regions, bee balm prefers full sun, but scorching California summers can sometimes be a bit much, so you may want to place your bee balm in where it will be protected from direct sunlight in the hottest part of the day. On the flip side of the calendar, your bee balm plant may die back to ground level in the winter, but don’t panic. Simply cover the area with mulch and it will be back when temperatures warm.
Bee balm pests and diseases
Powdery mildew is really the only problem that occurs with bee balm. You can protect your bee balm from powdery mildew by avoiding overhead watering and by pruning for good air flow. Fungicides can be used with marginal success.
Caring for bee balm
Bee balm is a low maintenance plant. You will want to provide it with a layer of compost each spring, covered with mulch, for good soil health. It may need to be watered during the peak of summer and be sure to remove spent blooms (deadhead) to encourage fresh flowers throughout the growing season.
So, sooth your senses and savor the site of butterflies and bees in your garden with bee balm!
Flies with mohawks are out to save your garden!
A tachinid fly looks like a small, sturdy house fly with a mohawk on its rear end. These tiny flies use many common garden pests to feed their young. Let’s find out how.
Tachinids as parasitoids
Tachinid flies are second only to parasitic wasps in pest control. Different tachinid species make use of different hosts in a number of ways. Most are parasitoids, which means they end up killing their host, while some are parasitic, which means the host may live. Tachinid flies parasitoid host insects to provide a guaranteed food source for their offspring. To parasitoid a garden pest, tachinid flies use several different methods. They may lay eggs on leaves favored by preferred caterpillars. When the larvae hatch, they are consumed by the caterpillar along with the leaf. Once inside the host, the larvae (maggots) begin their own feeding. Other tachinid species glue their eggs to the body of a host. When the eggs hatch, the maggots start feeding. Yet others using a piercing ovipositor (egg depositor organ) to inject the host with the eggs. Maggots feed until they are ready to pupate. Then, they drop to the ground and a hard casing forms to protect them as they morph into an adult fly.
You can attract tachinid flies to your garden or landscape by providing pollen and nectar for the adults from flat-topped (carrot, dill, yarrow) and composite (rudbeckia and aster) flowers. These beneficial insects also feed on aphid honeydew.
So, before you grab the fly swatter, take a closer look to see if that picnic pest is sporting a mohawk on its rear end.
Big-eyed bugs are your friend.
There are several different members of the Geocoris, or big-eyed bug family, and all of them are predators. This means they love to eat the pests that suck the life out of your garden plants, spreading disease as they go. The more big-eyed bugs you have in your landscape, the better.
Big-eyed bug diet
Gardeners should appreciate big-eyed bugs. These predators feast on small caterpillars, flea beetles, mites, cabbage loopers, whiteflies, and many different insect eggs. Research has shown that a single big-eyed bug nymph may consume up to 1,600 spider mites in its lifetime!
Attracting big-eyed bugs
You cannot currently purchase big-eyed bugs, but you can certainly lure them in with plants that provide nectar for when prey is scarce. While many beneficial insects prefer the flowers of carrot, fennel, and onion, big-eyed bugs prefer yarrow above all else. Yarrow is a sturdy, attractive border plant and it takes very little care to stay attractive.
Plant some yarrow today for your local big-eyed bugs!
Cattle panels, or livestock panels, make it easy to grow vertically.
Manufactured for the farming community, cattle panels, also known as stock panels, are used to modify corrals, create paths, and move livestock from one place to another. Being made for the rigors of farming and livestock, these panels are durable.
Cattle panel description
Cattle panels are made out of heavy duty 4 gauge (1/4”) galvanized rods that are welded into a grid. Most livestock panels are quite large, usually 16 to 20 feet long and a little over 4 feet wide. They are surprisingly affordable, at $20 to $30 each. [Getting them home can be tricky.] Hog panels are similar, except they are 3 feet wide, and the squares are more narrow along one edge. Once nice thing about stock panels is that you can cut out the horizontal rods along one edge to make legs that can be stuck in the ground for added support. If a full-sized panel is bigger than your garden space can handle, have the seller cut it in half for you, and then you’ll have two panels! Admittedly, this metal is sturdy, so bending (or cutting) it takes some effort. Cutting these panels requires the use of bolt cutters and some arm muscle. Gloves are a good idea whenever handling stock panels, too. Once the job is done, however, your garden will have added vertical space and it is easy to repurpose your stock panels as the seasons change.
Advantages of growing up
Apartment balconies, strips of ground between a house and a fence, and areas next to walkways are just a few places where you can get more out of your garden by growing vertically. Not only does growing vertical take up less space, it often improves air flow, reducing fungal diseases and making plants healthier than they would be spreading out on the ground. Healthier plants are better able to defend themselves against pests and disease, so you don’t have to resort to chemicals.
Ways to use cattle panels in the garden
Because these panels are so sturdy, they can be used in several different ways in the garden. Here are just a few ideas to get you inspired:
Which plants get trellised?
Many different plants can be trained up a stock panel: pole beans, peas, cucumbers, melons, and squash come to mind for most people, but raspberry and blackberry canes can also be trellised using cattle panels. Tomatoes, too, can be coaxed into growing up and around these panels, gaining support similar to what they would get from a tomato cage. Grapes, gourds, and even pumpkins can be trellised on stock panels, but heavier produce may need a hammock for added support, especially as some of them can become quite large!
Cattle panels are not your frail, fancy trellises, prone to rust and breakage. These suckers are sturdy and will last for many years in your garden.
Blight is a symptom of plant disease.
One day, your plant looks lush and healthy. The next day, several leaves are yellow and then turn brown. Stems, flowers, and branches also turn brown and then die. What can cause this sudden, severe damage? It might be blight.
Blight is a symptom
Blight is not a disease. It is what several different plant diseases look like. The initial symptoms appear suddenly and spread very quickly. Leaves, fruit, stems, and flowers can all be affected. The first symptom is tiny lesions on leaf tissue. This is where the bacteria or fungi first enter the plant, usually through small tears. The pathogens may also enter through vulnerable new growth. What starts out looking like leaf spot soon covers entire areas of a plant. Leaves and flowers suddenly lose all their green and turn pale yellow (chlorosis), followed by spotting, browning, withering, and dying.
Blight is most commonly seen on tomatoes and potatoes (nightshade family), and on apples and pears (pome fruits). Ornamental plants are not exempt. Here is a list of the most common blight diseases:
How to control blight
Since blight enters plants through wounds and tender new growth, there are three ways you can reduce the likelihood of blight occurring in your garden:
These are especially important when temperatures of 75° to 85°F are expected to be accompanied by rain. Pruning and feeding stimulate new growth that cannot defend itself. Also, do not irrigate trees while they are in flower. Monitor plants closely after favorable conditions have occurred and completely remove and destroy any infected tissue. This means cutting several inches below infected tissue, using pruners that are dipped in 1 part bleach and 9 parts water between each cut. This reduces the spread of the disease. Blossom sprays can be used on trees that have experienced blight in the past. Fixed copper sprays may provide some protection.
What summer picnic would be complete without watermelon?
Sweet, refreshing, and adaptable, watermelon is another easy-to-grow addition to your foodscape.
Botanically, watermelon is a type of berry called a pepo. It is also a gourd. As a member of the cucurbit family, watermelons are cousin to cucumbers, squash, pumpkins, and other melons.
History of watermelon
Watermelons were cultivated 5,000 years ago, in Ancient Egypt. Watermelon seeds were even found in King Tut’s tomb! Watermelon ancestors were not the bright red, sweet fruits we know. In fact, the original watermelons tasted pretty awful. They were bitter and hard. People grew them anyway, because these melons could hold water for weeks and even months, if stored properly. [That’s how they got their name - get it?] Five thousand years ago, that was a really Big Deal. As plumbing became a thing, watermelons had to up their game. Over time, and with selective breeding, they became the sweet summer picnic favorites that we love.
How to grow watermelon
Watermelon plants (Citrullus lanatus var. lanatus) can take up some space. The 5-sided vines may reach 10 feet in length and the leaves are large. Plant watermelon seeds one inch deep in groups of 6 to 10 seeds. These seeds should be planted in ‘hills’ that are 3 to 4 feet apart. These hills are mounds of loose, rich soil two feet in diameter. Once seedlings emerge, save the best 3 and snip the others off at ground level. Mulch around the plants to reduce weeds and retain moisture. Individual watermelons can be grown in a container, but it should be large - at least 5 gallons. They can also be grown up trellising or on stock panels, but each melon will need a hammock.
In the Bay Area, it is best to plant watermelon in May and June, though seeds can be started two weeks after the last frost date. Seeds will not germinate at temperatures below 70 degrees F. Row covers can be used over seedlings to protect them from pests and to retain some heat. Watermelons prefer a soil pH of 6.0 to 6.8. Watermelons do require a significant amount of water to produce fruit, but avoid getting the leaves wet to prevent fungal disease. If the leaves wilt in the afternoon, don’t worry about it. If they stay wilted into the evening, check moisture levels. Once fruit starts to appear, you will want to get it up off the ground with some straw. This reduces the chance of belly rot. Reduce watering just before your watermelons ripen to increase sugar levels and intensify the flavor.
Watermelon pests and diseases
Like most plants in the Bay Area, watermelon are likely to be attacked by aphids, cutworms, crickets and grasshoppers, armyworms, cabbage loopers, leaf-footed bugs, earwigs, flea beetles, leafhoppers, leafminers, nematodes, slugs and snails, thrips, whiteflies, and spider mites. As a cucurbit, watermelon is also subject to stinkbugs, cucumber beetles, and squash bugs. Many of these pests can be throated by dusting your melons with kaolin clay, a non-toxic fine powder that clogs up their breathing holes. Diseases that can affect watermelon include damping off, powdery mildew, downy mildews, verticillium wilt, root rot, fusarium wilt, angular leafspot, curly top, and white mold. Nearly all of these diseases are related to overhead watering, so don’t do it. Most watermelon varieties are resistant to anthracnose, but seedless watermelons (below) are not. Unlike other cucurbits, watermelon is not susceptible to cucumber mosaic and I have no idea why. Unsuitable environmental conditions can lead to blossom end rot, bitter fruit, blossom drop, and poor pollination.
One nice thing about growing watermelon is that you can plant the seeds in a raised bed, straw bale, or container, and then let the vine cover unplanted areas, or areas that are looking poorly. The large leaves shade the ground, stabilizing temperatures and making the soil more habitable for worms and beneficial soil microorganisms. Add a little mulch and you can be preparing that area for planting next season!
Add a watermelon plant to your foodscape every summer and save the seeds for next year's crop!
Note: What’s up with seedless watermelons?
Seedless watermelon production began in the 1990’s. This is how seedless watermelons happen:
Now you know.
Why do healthy plants fail to set fruit?
Your plants look lush and healthy. There are plenty of leaves and blossoms. You’ve been watering and feeding and mulching, just the way you are supposed to, and still not fruit. Why not?
Assuming that your plants are otherwise healthy, not diseased or water stressed, there are several reasons behind fruit set failure. The most common are lack of pollinators, too much heat, not enough light, and the wrong fertilizer.
Lack of pollinators
While many crops, such as tomatoes, are self-fertile, the lack of bees, flies, butterflies and moths, and even wind can reduce the number of fertilized flowers. Unfertilized flowers cannot produce fruit. You can attract more pollinators into your garden and landscape with colorful flowers that offer a variety of landing pads. Plant flowers in clusters, rather than singly, for the best results. You can shake plants very gently to increase pollination rates.
Too hot to fruit
One of the most common reasons why blossoms do not transform into fruit is heat. As temperatures rise, plant life processes slow down. Most spring temperatures are pretty mild, but a few scorching hot days can ruin everything, at least for a while. This is because pollen loses its viability between 85 and 90 ºF. So it won’t matter how many bees stop by for a visit or how healthy your plants are. It simply can’t happen. Luckily, most plants continue to produce flowers beyond the brief heat wave and the pollen in those flowers can produce fruit. Note, hybrid plants tend to be more sensitive to temperature fluctuations.
Most fruiting plants need six to eight hours of sunlight to produce. If growth is leggy and etiolated, it may be that they are not getting enough light.
Fertilizer, a balancing act
All plants need good nutrition to produce fruit. Unhealthy plants simply do not have the resources to produce a decent crop. At the same time, too much nitrogen can lead to excessive vegetative growth, and even blossoms, and still no fruit. Insufficient phosphorous can also cause reduced flowering and fruiting, but that is rarely a problem in the Bay Area. Before adding phosphorous (which we generally have in excess), conduct a reliable soil test (not the OTC variety).
So, if you are watering your plants properly and they are getting enough light, you may simply need to wait out the unfavorable conditions, or you may need to alter your fertilizer applications.
Epinasty refers to the way leaves and stems turn downward when their tops grow faster than their bottoms.
While we all know that many plants move to follow the path of the sun each day (phototropism), sometimes plant movements are more random. These are called nastic movements. Epinasty is a nastic movement. Hyponasty is the opposite of epinasty.
The weight of a heavy flower or fruit is an example of mechanical epinasty. Over time, the upper portion of a stem grows longer and faster as the weight of the fruit or flower pulls downward.
The most common cause of epinasty is ethylene. Ethylene is a gaseous plant hormone that helps fruits ripen. It is also a major survival tactic in cases of flooding, either temporary or permanent. Let me explain. When roots experience flooding, they generate an amino acid that I cannot pronounce, but botanists call it ACC. ACC is the precursor to ethylene. ACC moves up the xylem where it is turned into ethylene gas. This ethylene stimulates roots to create hollow tubes that connect to adventitious roots. These tiny roots and tubes are used to draw oxygen into the plant. Other signs of ethylene exposure include chlorosis, thickening stems, petal loss, and deformed or aborted flowers. Epinasty from ethylene gas is common among plants grown in greenhouses with poorly maintained propane or natural gas heaters.
If your tomato plants are exhibiting downward curling leaves, it may be that the soil needs more time to dry out between waterings.
Bite into a cucumber and, instead of crisp deliciousness, you get a bitter taste. What happened?!!?
Fruit can turn bitter for several different reasons. Unfortunately, once a plant produces bitter tasting fruit, you may as well cut it off at ground level and start again, because most of the fruit it will produce from then on will have the same taste. Also, the chemicals that cause the bitterness can make you sick. In extreme cases, they can even kill you. So, what makes fruit turn bitter and how can it be prevented?
Causes of bitter fruit
The bitterness is caused by chemicals, called cucurbitacins, that are always present in the roots, leaves, and stems of these plants. When the plant becomes overly stressed, it increases the production of cucurbitacins, which then make their way into the fruit. Scientists believe these chemicals are intended to discourage feeding by herbivores (and us). Common causes of stress that leads to bitter fruit include:
Steps to prevent bitter fruit
If your cucumbers have started turning bitter, you can still eat much of the fruit, simply by peeling it and tossing the stem end into the compost pile. If it still tastes bitter, compost it. The chemicals will disperse and break down.
Help your cucumbers, melons, and summer squash stay sweet with proper irrigation and a little sun protection.
Temperature impacts every stage of plant growth and fruit production.
We all know that most plant life processes stop when it gets really cold outside, but did you know that the same thing happens when it is hot?
Temperature sweet spots
Each plant species has a minimum, maximum, and optimal temperature range for its different life processes: germination, seedling growth, vegetative growth, and reproductive growth. Some plants, such as peas, lettuce, broccoli, and spinach, prefer cooler weather (60 °F), while squash, melons, peppers, tomatoes and corn prefer hot weather (80 to 90 °F). The normal (phenological) responses to temperature are what make our harvest possible. And sometimes we get 90 °F weather in April.
Plant responses to heat and cold
Just as the symptoms of not enough water look a lot like the symptoms of too much water, plants respond to both temperature extremes in very similar ways. (Their options are limited.) At first, they close the tiny pores, called stoma, on the underside of leaves to retain moisture. If this isn’t sufficient protection, they wilt. Then leaves begin to dry and burn at the tips and edges, and tender new growth can die. Prolonged exposure can lead to twig and branch dieback, or complete loss of the plant.
What happens when it gets too hot?
Excessive heat (above 90 °F) can lead to water stress and sunburn damage. It can also interfere with pollination. Pollen loses its viability at temperatures over 95 °F and seedlings die at 125 °F. While the Bay Area never sees temperatures that high, sunlight reflected off of hot pavement can easily scorch nearby plants. In crops such as corn, a sudden heat wave can reduce your harvest by 80 to 90%! Studies have shown that high temperatures can reduce the amount of time a plant takes to produce fruit, lowering both size and quality. Plants also tend to stay smaller. You cannot control the weather, but there are things you can do before, during, and after planting to help your garden and landscape plants survive temperature extremes.
When water isn’t enough
Deep roots and good health go a long way toward helping a plant protect itself. Shallow root systems dry out quickly and are more sensitive to heat and cold. Watering plants deeply and allowing the soil to dry out between waterings encourages roots to go deeper. And sometimes water isn’t enough. A thick layer of aged compost or other mulching material placed around trees, shrubs, and other plants can stabilize soil temperature and provide a slow-release of nutrients. Just be sure the mulch does not touch the trunk. Avoid using fertilizer when extreme temperatures are expected, and be sure to leave as much leaf cover as possible. Excessive pruning can make plants vulnerable to heat and cold. Artificial protection from the elements can take the form of shade structures, row covers, pergolas, umbrellas, and shade cloth. Blocking even a little sunlight on a hot day can help your plants get through the worst of it without sunburn damage or water stress.
An ounce of prevention
You can eliminate much of the work related to temperature extremes by selecting plants best suited to your microclimate (natives are an easy choice), and place them in locations suitable to their species. And be sure to install plants at a time of year when they will have enough time to develop a strong root system. Finally, have your soil tested by a reputable lab, to find out exactly what you are working with, and continually strive to improve soil structure.
Healthy soil makes healthy plants. Healthy plants can tolerate heat and cold better than plants marginalized by poor soil, insufficient irrigation, or improper care.
I hope this information inspires you to grow more of your own food. You can ask your garden questions on my Home page.