Click on a month to learn more about common Bay Area gardening chores.
Potential for frost
Sudden rain and shorter days
Just as natural cycles cause plants, animals, and insects to draw closer to home, move around or grow less, and to retain resources, we can copy those behaviors to the benefit of our garden and landscape. While there is still time to plant winter crops mentioned in the October notes, and cover crops, November is an excellent time to clean up and prepare for the holidays and colder weather.
Fall clean up
If you haven’t already, this is a good time to discard any plants that are not thriving. Annuals and other garden plants that have completed their life cycle are best removed by cutting at ground level, rather than pulling. Pulling plants up by the roots disrupts microbe populations, which interferes with soil health. Also, by cutting plants off at root level, you may get a surprise next spring when that annual turns out to be more tenacious than you thought!
Before the rains get started, this is a good time to look through stacks of materials to see what needs cleaning, repairing, sharpening, or discarding. Plant saucers and pots should always be scrubbed clean and then soaked in a solution of one part bleach to nine parts water for ten minutes to prevent the spread of disease. They should also be stored upside down to prevent water collection and mosquito breeding. [I used the staves from a half barrel, that had started to rot, to create a simple storage system for planter saucers. I just drilled screws in from above. It makes them easy to see and they do not collect water.]
As trees drop their leaves, it is a good idea to think about whether or not you should rake. Fallen leaves make excellent compost or mulch but they will interfere with your lawn, if you still have one. Leaves should be removed from lawns and concrete (due to staining), but there is no reason that I know of for removing leaves from anywhere else. From my point of view, fallen leaves are plant foods and soil amendments that have been around a lot longer than us.
If you have rain barrels in place, be sure to check all the connections and spigots before the rain starts. If you haven't yet, this is an excellent time to take a power washer or your garden hose to the interior of your rain barrels. Throughout the year, various microorganisms can take up housekeeping in these moist, protected areas, and some of those critters can cause illness in pets, plants, and humans.
Sooty mold fungus
Remember those aphids, mealybugs, whitefly and scale bugs that tormented your garden all summer? Well, they left behind copious amounts of honeydew that creates the perfect growth medium for mold. Sooty mold is common in the Bay Area and is easy to recognize as black smudges on leaves and fruit. While the mold can be washed off food and eaten safely, it can be devastating to host plants. The mold actually blocks sunlight from entering the leaves, slowing or even halting photosynthesis. Ants carry the disease, so slowing ant traffic can be a big help. The easiest way to block ants is to wrap tape around the trunks of trees and apply sticky barriers to the tape . Also, trim branches away from buildings, fences and other plants, and use ant bait. While you are at it, November is also the perfect time to caulk your home against winter invaders.
The recent devastation in northern California reminds us to be proactive when it comes to fire safety, Change the batteries in your smoke detector, have your chimney and/or furnace inspected, and look at your landscape with an eye for fire safe gardening.
Cooler temperatures may reduce the number of pests in your garden and landscape, but imported cabbage moths and Harlequin bugs will be doing their very best to wreck your cole crops. Cabbages, cauliflower, and broccoli leaves should be checked frequently for cabbage moth eggs (tiny clear-ish white flecks on the underside of leaves), small (and some not-so small!) green cabbageworms, and clusters of drum-shaped Harlequin bug eggs. These eggs can simply be brushed off and the hatched larva will generally be unable to find their way back to the host plant. You can also use row covers, once you are absolutely certain that you have removed all the eggs. [Check every few days anyway, just in case.]
It may be difficult to imagine, after all of our 90°F October weather, but the Santa Clara Valley's first frost date is November 15th. Frost dates are statistical averages over time. They are not written in stone. I can tell you, speaking from experience, it is far easier and more comfortable for you to prepare your plants' frost protection before it is needed. Old bedsheets, row covers, and even umbrellas can provide all the protection that's needed, just be sure to make it so that the fabric does not actually touch the plant.
You can stabilize soil temperatures, reduce weeds, and slowly add nutrients to your soil with mulch. You can buy different sizes, colors, and materials, or you can contact local tree trimming companies for free mulch. Wherever it comes from, be sure that it is disease-free and that it won't float away when the rains comes.
If you planted saffron crocus in an earlier spring, you should be harvesting your saffron crop right about now. Once you have your garden cleaned up and your tools put away, grab a good garden book and start planning for spring!
Orange-red leaves fall
Torn from brittle stems, take flight
Soon for winter sleep
Bay Area Octobers are the perfect time to prepare for a lovely spring. This is the season for removing weeds, dead plants, and pest habitats. It is also the time to plant winter crops. Best of all, October is the perfect time to install your very own herb garden! Cooler temperatures and (hopefully) rain provide conditions needed for thriving winter vegetables, spring blossoms, and ongoing herbal culinary treats.
Bring out your dead!
Tomatoes, peppers, squash, and many other garden fruits and vegetables are now at or near the end of their productive lifecycle. While tomatoes are technically a perennial, most tomato plants are treated as annuals. Rather than pulling spent plants from the ground and destroying soil microbes, it is far better for soil health to cut the plant stems and stalks off at ground level. This allows roots to die off slowly, in the ground, providing soil microbes with the time they need to adjust. Chop thick stalks into smaller pieces to improve your compost pile’s natural processes when adding last summer’s plant material to the pile.
Fall flower care
This is also the time to continue weeding and deadheading flowers. Removing blossoms properly allows flowering to continue for as long as temperatures allow. The only exception is roses. To encourage your rose bushes to enter a much-needed dormancy, it is better to start removing only the flower petals and leaving the rose hips attached to the stem. Be sure to dispose of seeded weeds, rather than adding them to your compost pile. If you are raising chickens, weeds with seeds make excellent forage.
Prepare winter beds
Collect fallen leaves from under fruit and nut trees, rose bushes, rhododendrons, camellias, and azaleas to prevent the spread of pests and disease and add them to your compost pile. Pine, juniper and oak do not need leaf litter removed. Add a thick later of mulch or aged compost on top of all your planting beds. This will help prevent erosion and add nutrients to the soil for next year. Legumes such as cowpeas or fava beans can also add nitrogen to the soil, as long as they are not allowed to go to seed. Bare earth should be covered with a thick layer of wood chips, which can be gotten for free from local tree trimmers. Wood chips prevent erosion, add nutrients, and slightly acidify the soil. They look nice, too!
Spring bulbs & winter crops
Nothing says spring like brightly colored bulbs emerging from the barren muck of winter. Now is the time to shop for those spring bulbs and put them in the refrigerator (not the freezer) for 6-8 weeks. Use a paper or mesh bag to allow the bulbs to breath. You will want to keep them away from apples, which emit ethylene gas and will cause the bulbs to sprout too early. If you already have bulbs or perennial flowers, this is a good time to dig them up and divide them to allow for better growth in the spring. In the Bay Area, autumn is the perfect time to winter crops from these plants families:
This is also a good time for planting spring wildflower seeds, as well as native plants, shrubs and trees.
Create your very own herb garden!
You can create an herb garden in your yard, on a balcony, or even inside your home. The following herbs and spices can be planted now to provide years of delicious meals and lovely displays, wherever they are grown:
When spring comes around, you can add basil, anise, borage, oregano, lemon grass, marjoram, and sage to your herb garden for a tasteful gardening experience!
Which plants are you putting in this October?
Cooling, shorter days
Succulent harvest abounds
Prepare now for cold
Harvesting the fruits of all that labor and preparing for winter keep the September gardener busy. Deadheading, clearing away debris, and composting spent annuals all help to prevent future problems with pests and diseases.
Many apple varieties are ready for harvest (assuming the birds have left any uneaten). Other apple varieties will need some colder weather to sweeten. If you notice small brown, corky areas under the skin, it is called bitter pit. Bitter pit, like blossom end rot in tomatoes, is caused by a calcium deficiency early in the spring. In this case, however, the condition can be treated on future crops by spraying the leaves with calcium nitrate just after bloom and again one or two months later. Use one tablespoon per gallon of water.
Carrots prefer loose soil, but shorter varieties perform well enough in our heavy clay. The addition of compost can help aerate the soil and provide valuable nutrients. Carrots should be planted no more than 1/2” deep and plants should be thinned to 3” apart, to avoid forking and twisting. Water regularly but allow some drying to prevent cracking. Successive plantings provides an ongoing harvest. Carrots can be planted between landscape perennials for productive use of space.
If rose leaves are exhibiting neat round or oval holes in them, it is probably the beneficial leaf cutter bee and should be ignored. The sections of leaf are used to line brood cells, which are also filled with nectar and pollen.
Squash and cucumber plants are susceptible to a disease carried by aphids and cucumber beetles. Mosaic virus causes leaves to become mottled and stunts plant growth. Fruit may become white. Diseased plants should be removed and put in the trash. Do not add to the compost pile.
As nights become cooler, it is common for powdery mildew to strike. Affected leaves should be removed and thrown in the trash, and overhead watering should be avoided.
Gnawed fruit, empty snail shells, and tiny black pellets are all signs of roof rats. These pests can infiltrate your attic, crawlspace, garage, storage shed, and trees. Rat traps are an excellent way to remove resident rats. Keeping pet and livestock food sealed up and harvesting crops as soon as possible will help make your yard less desirable to the local rat population. Since rats can carry serious diseases and damage electrical wiring, it is worth the effort to get rid of rats.
If leaf stippling and tiny webs are seen, spider mites are probably the reason. Spider mites prefer dusty conditions, so spraying infested plants with the hose can help. Using broad spectrum pesticides is not recommended because they will kill the spider mites’ natural predators. Heavy spider mite infestations can be treated with insecticidal soap or horticultural oil.
September is the time to plant many winter crops, including artichoke, arugula, beets, bok choy, cabbage, carrots, cauliflower, chard, cilantro, collards, dill, fennel, kale, leeks, parsnips, peas, radishes, rutabagas, spinach, and turnips.
Enjoy the fruits of your labor!
Foggy mornings pale
Seared from sight by blazing sun
Nectarine juice drips
Aside from watering, August may seem like the perfect time to take a break form the heat, but there are still plenty of garden tasks to choose from!
While ants do help aerate the soil, they can also damage crops and spread disease. Fruit trees can be protected with sticky barriers. Boric acid bait traps can be an effective control method, just be sure the baits are placed where children and pets cannot reach them.
Unlike other trees, which are pruned when they are dormant, apricot trees are best pruned in summer. Apricot trees are susceptible to a fungus called Eutypa dieback, which can infect trees if rain reaches fresh pruning cuts.
This is the time of year when Japanese beetles, dried fruit beetles, and June beetles are the easiest to see (and eliminate). Japanese beetles will skeletonize many plants. These pests tend to cling to their favorite foods and are easy to knock into cans of soapy water. [I used to pay the neighborhood children a nickel for every June bug they eliminated - very useful in Virginia!] June bugs are clumsy fliers and easy to slap down with a net. Both can be fed to chickens. Dried fruit beetles and June bugs do not bite or sting and dogs can be trained to chase and kill them before they lay eggs in the soil. These eggs will later hatch and the larvae will devour lawn, ornamental, and other plant roots.
Just as in April and June, oranges and other mature citrus trees should be fed one-half pound of nitrogen in August. Blood meal is an excellent source of nitrogen, without all the fillers. Ammonium sulfate is another good source of nitrogen.
This is the time of year when all that hard work and patience really pay off. Keep plants healthy and enjoy the fruits of your labor by harvesting frequently. This reduces the number of places where pests and diseases can hide. This also prevents many plants from going to seed and ending fruit production. When harvesting tree fruit, be sure to keep a look out for mummified fruit. Remove mummies and dispose of them in the trash, not the compost pile.
If you have a lawn and it has not turned completely brown, allow it to grow longer than you would in cooler months. Taller grass protects the soil and helps retain moisture. And be on the lookout for masked chafers and southern chinch bugs.
Mite infestations often look like nothing more than light webbing around leaves and stems. This webbing is followed by leaf stippling, chlorosis, and leaf drop. Water-stressed plants are more susceptible, as are dusty plants. Mites are related to spiders. Adults have eight legs, but the young only have six. Spraying pesticides often backfires because mite predators, such as lacewings and pirate bugs, are killed. Often, you can use a soft-bristled brush to dislodge these pests.
By August, most rain barrels have run dry, making this the perfect time to clean out any debris in the remaining grey water, along with any mosquito larvae. West Nile Virus, Zika Virus, and many other diseases are transmitted by mosquitoes, so it is important to regularly eliminate any standing water. Mosquito dunks should be added to any standing water every 30 days.
Hot weather means trees need more water. Trees planted in a lawn that is being watered regularly will still need a deep watering 2 or 3 times during the summer, or more, depending on the weather. Stand alone mature fruit and nut trees will need a deep watering every 3 - 4 weeks, while younger trees will need to be watered every 2 weeks. Ideally, there is an irrigation ring around each tree at the drip line.
August is an excellent time to start seeds for winter crops. Spinach, beets, lettuce, arugula, broccoli, Brussels sprouts, cabbage, cilantro, bush beans, fava beans, leeks, radishes, and peas can all be started in small containers for transplanting after summer crops are done. This gives you a head start on the cooler growing season, just be sure to keep the soil moist. A thin layer of vermiculite can help retain moisture.
Greens bolt and wither
Searing heat and glare above
Seek shade and cool water
July in California is too hot to spend much time outside. Early morning and late evening make working in the garden far more comfortable, but leave most of the heavy work to the plants as they produce leaves, stems, and fruit in response to all that sunlight. The best things you can do for your garden in July is irrigate properly and monitor plants for pests and diseases.
Monitoring for pests and diseases
You know what they say about an ounce of prevention. Well, here are a few helpful ideas that work to prevent problems in the garden before they have a chance to get started:
It’s all too easy to forget about the trees in your landscape, but an extended drought like ours can be devastating. Trees are a big investment of time and space, so be sure to include them in your watering plan. The only exception is our CA live oaks - they are used to hot, dry summers and watering them only makes them susceptible to disease.
On scorching hot days, container plants may need a drink practically every day. Just be sure to avoid overwatering - a drowning plant looks an awful lot like a plant that’s dying of thirst. An inexpensive moisture meter ($10-15) can help prevent irrigation errors.
There is no fixed magic formula for watering plants in the garden. There are simply too many variables, such as plant variety and age, soil type, fertilization practices, sun and wind exposure, overall plant health and life stage - you get the idea. The best way to assure that your garden plants are getting the water they need is to learn as much as you can about the specific varieties and their water needs. This information will help you to provide them with the growing conditions they need.
If you still have a lawn, go ahead and let it turn brown over the summer. The root system will stay alive with very little water, and it will come back in the fall after temperatures go down. [I use water from my washing machine with no negative results and a lawn that stays green far longer.]
As you lounge in the shade with an iced tea, remember that July is an excellent time to consider what cool season crops can be added in fall!
Longer days of sun
Burst forth fruits and leaves
June is a busy month in the garden. Summer heat means irrigation and ants seem to be everywhere. Fruits and flowers are the name of the game when it comes to June garden chores.
Ants & aphids
The bane of all gardeners, aphids are in full force in June. You may see ant trails in trees or curled leaves. Ants and aphids have a mutually beneficial relationship that may not kill garden plants, but they can carry diseases that will. They can also make fruit and vegetables inedible. Monitor for ants and aphids at least twice a week. If ant trails are seen, wrap tree trunks with tape and apply sticky barriers. This sticky goo will prevent ants form protecting and farming the aphids and halt the spread of many diseases. Aphid populations can then be reduced with a powerful spray from the hose. Adding plants that attract beneficial insects will also curb aphid populations.
Armored scale are parasites that suck the living sap from shrubs and trees. In June, these difficult to control pests are in a crawler stage that is easier to defeat. Monitor plants for armored scale infestations. Apply horticultural oil (not dormant oil) every month in summer to affected plants.
Blossom end rot
Are there brown depressions on the bottom of your tomatoes? This is caused by not enough calcium or irregular watering. Since most soils have adequate calcium, watering is usually the culprit. Without regular watering, the calcium in the soil cannot reach the plant. Mulching can help. Water tomatoes regularly, allowing them to dry out between waterings.
Blackened twigs & branches
If twigs and branches are turning dark or burnt looking, you have a problem. Generally, the damage starts at the tips and moves toward the body of the plant. This can either be dieback or fireblight. In either case, all you can do is remove the damaged tissue, cutting well below the visible infection and cleaning your clippers between each cut. Take a close look at the cut to make sure healthy tissue is visible. To reduce the chance of these fungal diseases attacking fruit trees in June, be sure to halt watering during the bloom and avoid adding nitrogen. Nitrogen stimulates new growth that is especially vulnerable to infection.
In California, most soils contain adequate nutrients for citrus growth, except nitrogen. One-year old trees will need 1/10 of a pound of nitrogen, while mature trees need approximately 1-1/2 pounds. These amounts should be divided into three different feedings in April, June and August. Blood meal is an excellent source of nitrogen, without all the fillers, or you can purchase a balanced product that contains zinc. Spread the fertilizer evenly over the entire root area and water in.
QUARANTINE WARNING: MOST OF SANTA CLARA COUNTY IS UNDER QUARANTINE FOR CITRUS, DUE TO THE ASIAN CITRUS PSYLLID. CHECK THIS MAP TO SEE IF YOU ARE AFFECTED.
Container planting is an excellent way to garden in small spaces and to add art and color to the landscape. However, June’s high temperatures can dry out containers very rapidly. To make matters worse, frequent irrigation can also leach out nutrients. It’s a dilemma. Gardeners can reduce these problems by not using unglazed clay pots, which dry out even faster. Dark plastic should also be avoided because it can get too hot and cook the roots. Good drainage is important, but you can help container plants hang on to water and nutrients by using potting soil, rather than planting mix.
June usually provides an abundance of fruit. If damaged fruit is seen, take a closer look. If the fruit looks chewed on, it’s probably rats or squirrels. Personally, I use Bobbex-R to deter these destructive, disease-carrying pests. My dogs enjoy helping out, too! I used traps to kill half a dozen rats when we first moved in, but I haven’t seen signs of any since. It’s a bit disgusting, but it works.
Does the fruit show stab marks? That’s usually birds. The only way to keep birds out of fruit trees is with netting or a tree cage. The netting is a royal pain to put up and take down, but it’s surprisingly easy to build a permanent tree cage. Most birds will only take a bite or two out of dozens of fruits, ruining a crop. Netting placed directly on the plant does not protect fruit near the netting. I also discourage birds by hanging old CDs in my fruit trees. Breezes cause them to spin and reflect light, which seems to alarm the birds some of the time..
Spent ornamental flowers should be removed to stimulate new growth. When deadheading, don’t clip just below the flower. Instead, look down the stem for a leaf connection that shows bud growth. June deadheading is also a good time to prune for improved shape, structure and air flow.
Another common pest, earwigs are second only to slugs and snails in garden destruction. Even though they eat aphids, the damage they cause doesn’t balance out. Trap earwigs in moist, tightly rolled newspaper or cardboard tubes. Earwigs will gather in these bundles after their nightly feeding and you can toss them in the trash in the morning.
If you haven’t already, June is a good time to check irrigation systems for leaks. Drip systems should be flushed and emitters checked for clogs. This is also a good time to test to see where, exactly, sprinklers are spraying and where they are not. There’s no sense in wasting precious water in urban drool and the spray should never hit tree trunks.
Mulching is one of the best things you can do in the garden, especially in June. Mulching stabilizes soil temperatures, reduces weeds, and helps the soil retain moisture. Aged compost, placed on top of the soil, is mulch. Tree trimmings make excellent mulch and they can be acquired for free from tree trimming companies!
As roses give us their lovely June blooms, they may also put out suckers. Most modern roses are actually grafted onto hardy root stock that will not produce those lovely flowers. If new growth is emerging from underground, rip them out. Desirable canes, on the other hand, will grow out of aboveground buds and should be allowed to grow (assuming they won’t result in crossed canes or poor air flow. Blackspot, rust, and powdery mildew are common fungal diseases of roses. Proper pruning can reduce the chances of these diseases occurring. Diseased leaves should be removed and discarded.
Be sure to put on your sunscreen, wear a hat, and keep those tools clean and sharp as you enjoy the garden in June!
As busy as bees
We pierce the warming topsoil
With dreams of freshness
May is one of the busiest months in the garden. Temperatures have warmed enough for us to begin planting in earnest. Weeds, pests, and beneficial insects are out in force. And it's gorgeous outside!
Bees are very active in May. There is simply so much pollen and nectar to collect! Sometimes, a honey bee colony may swarm. If you see a swarm, don’t panic. As in any other time when working around bees, remain calm, move gently, and give them their space. Contact your local Master Gardeners to have swarms removed.
Bulbs & other flowers
If flowering bulbs were looking crowded during the recent bloom time, delay digging them up to separate until after all the foliage is completely dry. Bulbs pull important nutrients from these leaves to help start up again next spring. Bulbs that are dug up and separated can be replanted in a new location, gifted to friends, or stored in a cool, dry, dark location until fall. If you want fall blooms, plant now.
They are countless varieties of plants that perform well in containers. Do them all a favor in May and get them off that soon-to-be hot concrete patio. Creating even the smallest space under container plants can reduce the roasting effect, which means they will need less water. Speaking of water, warmer temperatures mean container plants will start drying out more quickly. Water as needed.
Many flowers are in full bloom in May. To encourage plants to continue creating blooms, remove spent flowers as soon as they are seen. This also reduces habitat for many pests and diseases. Pinch back borage, petunias, and fuchsias to prevent plants from becoming top heavy.
May is the time fireblight shows itself in the Bay Area. Fireblight is a bacterial disease that makes plants look as though they had been damaged by fire. It attacks apples, pear and quince, most often, but can also infect ornamentals, such as toyon and pyracantha. Very often, the growing tip folds over into a shepherd’s crook shape. Fireblight can kill a mature tree, so complete removal of any diseased tissue is critical. Dip clippers into a 1 part bleach, 9 parts water solution between each cut to prevent reinfection. The final cut should be 8-12 inches below the diseased area.
May should be the time when fruit trees are covered with immature fruits. Thin those fruits now or regret it later. Too much fruit in one place means none of them taste as good as they might have. It also creates habitat for pests and disease. Apples should be thinned to no more than 3 fruits to a cluster, or one fruit for every 6 inches of branch. Apricots and other stone fruits need 4-6” between fruits for optimal growth, flavor, and sweetness. Also, be ure to check apples for codling moth damage.
If you have a lawn, be sure to water it as early in the morning as possible. Personally, I set my timer to 4:00 a.m. That way, the water isn’t lost to evaporation and the grass has time to dry out during the day, reducing the chance of fungal diseases. For the most part, I use water from my washing machine to water my lawn and it has been working very well. Check the lawn for weeds such as spurge, burr clover, and whatever happens to invade your neighborhood. When mowing, set the blade height as high as you are comfortable with in summer - taller grass shades the soil, reducing evaporation and protecting valuable earthworms and microbes in the soil.
Mulch & compost
Compost and mulch are two of the best things to add to any landscape. They both add valuable nutrients to the soil, improve soil structure, and stabilize soil temperature. In our heavy clay soil, mulch prevents the baked concrete look we have come to expect in summer. [An important note about soil additives - while it may sound right to add sand to clay soil, to reduce compaction, it ends up creating concrete. Don’t do it!]
Slugs & snails
Slugs and snails can devastate young May seedlings. Applying non-toxic slug and snail bait lightly around new planting areas can save the crop. While there are more effective baits, those made with iron phosphate are not toxic to pets and wildlife and I have found they work well enough.
This is the most welcome news of the season in the Bay Area. Nearly all summer growing plants (tomatoes, cucumbers, melons, squash, beans, corn, peppers, etc.) can be put in the ground in May. If you are using transplants, be sure harden them off gradually or they may lose much of their vigor and productivity. Hardening-off simply means placing them outdoors in a protected location for a few hours. Slowly increase the time over a couple of weeks. Be sure to stake tomato plants now, while they are small. And add straw under melon, squash, and strawberry plants to reduce fungal infection.
If Verticillium wilt occurred last year, it is important to plant members of the nightshade family (tomatoes, potatoes, peppers and eggplant) someplace else. Verticillium wilt is a fungal disease that shows as yellowing older leaves, at first. Then, as the disease spreads, wilting occurs. Young plants nearly always die. Since the fungal spores can remain in the soil for 10-15 years, crop rotation is the best prevention.
California’s drought is continuing, despite the fair bit of rain we have received so far. The truth is, the Golden State has always been drought-prone and we would be wise to learn to live accordingly. When water restrictions were first implemented, I vowed to take meaningful steps to reduce our water consumption. As a result, we now use only 25% of the water we used to use! Surprisingly, my garden has not suffered and neither have we. These steps can help you conserve water while still caring for the garden:
Just as young garden plants are really kicking it into high gear in May, so are the weeds. Take my word for it, pulling them while they are small, and before the soil is baked, is much easier than later. Weeds take precious water and nutrients from garden plants. The sooner they are gone, the better.
So, put on the hat and sunscreen and get out there in that May garden!
April chirps and sings
Splitting shells and seeds and blooms
April is a busy month in California gardens. With scorching summers on a not-too-distant horizon, flowers, weeds, and every other living thing are striding toward sunlight. Cool nights may hold this rampant growth in check for another week or two, but most gardeners have plenty of April garden tasks to keep them occupied.
Codling moth larvae can devastate apple, plum, pear, and walnut crops. The larvae pierce the fruit and burrow into its core, where it then feeds on the fruit, making it inedible. On apples, look for tiny dimples with a small hole in the center. These holes are usually filled with frass (bug poop). Trees should be monitored every week for signs of infestation. Infested fruit should be removed and discarded, to break the codling moth life cycle. Pheromone traps can be hung in isolated trees, but you need to understand that these traps attract codling moths to the tree. The traps are really a population monitoring device, not a control measure. Fruit can be bagged for protection, but this is a very labor intensive method. Kaolin clay application is an excellent organic control method. Heavy infestations may require the use of pesticides on the moths, before fruit is affected.
As flowers begin blooming, you can increase production by removing spent blooms. Take a look at buds further down the stem and clip just above a bud that points in the direction you want the new growth to go. This can help the plant structurally and allow for good airflow.
As difficult as it may be for gardeners to thin out fruit and young plants, it really is necessary for the optimal growth of remaining plants. April is the time to thin fruit on fruit trees, such as apricots, peaches, apples, pears, nectarines, and plums. Crowded fruit doesn’t get as big as it could and it encourages fungal diseases. Close-quartered fruit also provides great hiding places for pests. The best fruit grows from strong flower buds in full sunlight. The basic rule of thumb for thinning fruit is to leave one fruit per spur, with fruit 4-6” apart. Apricots, nectarines and peaches are normally thinned when the fruit is 1/2-3/4” in diameter. Nut trees do not need to be thinned.
Spring rains bring moisture that can cause many fungal diseases. Anthracnose, brown spot, powdery mildew, sooty mold, and Verticillium wilt should all be watched for and treated. Many of these conditions can be avoided with pruning that allows good air flow and irrigation that does not come from overhead. Overhead watering splashes millions of fungal spores onto uninfected plants, spreading the disease (plus, it wastes water through evaporation).
Irrigation & greywater
As temperatures rise, irrigation becomes more important. Container plants will begin to dry out and need to be checked every day. If the irrigation system wasn’t inspected in March, be sure to do it now. Greywater, from sinks, washing machines, and rain barrels can be used to irrigate ornamentals and lawns. I use water collected from the shower, as it heats up, to water edibles.
To add nutrients, reduce weeds, and to help retain moisture, nothing beats mulch. Wood chips and aged compost both make excellent mulch. To stop weeds from growing, the mulch should be at least 4” think. Be sure to keep mulch at least 8” away from tree and shrub trunks, to avoid fungal diseases.
If you have Navel orange trees, the crop will be ripening in April. Oranges left on the tree too long will dry out and become inedible. Instead, harvest the entire crop by the end of the month and you can make my new favorites, Cardamom Orange Marmalade, Orange Cumin Chutney and Spiced Oranges. Once canned, these delicious condiments make lovely gifts. You’ll want to be sure to save plenty for yourself - it’s that good! Valencia oranges will ripen during the summer and they make excellent juice. April is a good time to add nitrogen for orange trees. One-year old trees will need 1/10 of a pound of nitrogen, while mature trees need approximately 1-1/2 pounds. These amounts should be divided into three different feedings in April, June and August. Blood meal is an excellent source of nitrogen, without all the fillers.
QUARANTINE WARNING: MOST OF SANTA CLARA COUNTY IS UNDER QUARANTINE FOR CITRUS, DUE TO THE ASIAN CITRUS PSYLLID. CHECK THIS MAP TO SEE IF YOU ARE AFFECTED.
Fennel, arugula, rhubarb, and asparagus provide many years of food production and April is a good time to plant. Fennel and rhubarb will take up a good amount of space, so be sure to keep mature sizes in mind.
Temperatures have finally reached the point when gardeners can plant most herbs, leafy greens, and other salad ingredients. Lettuce, spinach, bok choy, basil, parsley, cilantro and radishes can be planted every couple of weeks for a continuous harvest until temperatures get too hot.
Many vegetable crops can be planted in April. Bush and pole beans, corn, cucumber, summer and winter squash, and tomato seeds put in the soil now will begin their journey toward fruitfulness. Be sure to read packet directions for planting depth, spacing, and sun requirements for the best results.
One of the most important April garden tasks is to get rid of those weeds. Since they can go to seed faster than everything else in the garden, pulling them out now will save you countless hours of work later on, in the summer.
Nascent roots and stems
Displace freshly warming earth
Chill nights slow their birth
Citrus pruning should not be started until after March 15th, but now is the time to seriously inspect for mummies. Mummies are those shriveled up, fuzzy gray oranges that house millions of fungal spores. When removing mummies, try to disturb them as little as possible, or cover them with a plastic bag before removing them from the tree. If a citrus tree shows signs of chlorosis (yellowing) on older leaves, it may indicate a nitrogen deficiency. Interveinal (between leaf veins) chlorosis usually means a micronutrient, such as iron or manganese, is needed. Our soil tends to be very low on iron, but you can’t know for sure without a soil test. After the danger of frost has completely passed on March 15th, give citrus trees a good pruning. Just be sure to keep a look out for nests. It’s that time of year!
Another common March task is to inspect and repair sprinklers, drip systems, and water collection systems. How do you know if you have an irrigation leak? It can be difficult to spot, especially if it is small. The most common indication is an area that gets and stays wet longer than everywhere else. Sprinklers should be aimed so that they do not hit tree trunks, walkways, driveways, or sidewalks. The former can cause fungal diseases and the latter creates wasteful urban drool.
March is also a good time to prune out dead branches and twigs from fruit and nut trees and ornamental trees and shrubs. It is easier to see the structure of each plant before it is covered with leaves.
If your roses haven’t already started producing leaves and blooms the way mine have, March is a good time to prune them for better airflow and structure. You can also start feeding roses in March, and you may need to spray for blackspot. Blackspot is a fungal disease that loves moisture. As dew collects on rose leaves, the fungus reproduces astronomically. You can use neem oil or baking soda with horticultural oil. Personally, I use a large fan on my roses in the early morning to speed evaporation of the dew. It seems to work well.
March is an excellent time to start planting your summer garden. In the Bay Area, you can now plant beans, squash, melons, corn, and peas directly into the ground. More delicate plants, such as tomatoes, peppers and eggplants, can be started in pots. Be sure to keep pots in an area where they get plenty of sun, but are still protected from nighttime cold. As you dedicate seeds to a specific location, make sure to read the seed package labels for things like mature size, thinning requirements, and sunlight needs, and be sure to use plant markers!
Slugs & snails
Our warming temperatures and moisture work together to create the perfect habitat for slugs and snails. These mollusks can devastate seedling in a single night, so be prepared. I urge you to follow the link to slugs and snails to learn more about the specific ingredients in different bait products. They are not created equally, and some can harm pets. Choose accordingly.
Walk through your garden in March and you are sure to see weeds coming up in every location imaginable (and a few unimaginable places!). Your Number One March garden task is to pull weeds. Since some weeds can go to seed in as little as a week, now is the time to yank them from the earth. Recent rains and busy worms have made it easier to remove weeds, roots and all, by softening the soil. Wait until later in the season and the ground will be hard and thousands of seeds will already be sown. Healthy weeds make great additions to the compost pile. Personally, I feed them to my chickens.
Enjoy the early blossoms!