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 onions, poppies, spring blooming bulbs, 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.
As trees drop their leaves, think before you 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. The only exception might be leaves that are exposed to a lot of car exhaust. You might not want to add those amendments to your soil. Also, really thick layers of leaves, more than a couple of inches, can interfere with soil respiration. If you have that many leaves, it is a good idea to chip them, or chop them with your lawnmower to speed decomposition up a little bit.
Cooler temperatures may reduce the number of pests in your garden and landscape, but imported cabbageworms, brown marmorated stink bugs, and Harlequin bugs, along with ever-present aphids, will be doing their very best to wreck your cole crops. Cabbages, cauliflower, and broccoli leaves should be checked frequently for imported cabbageworm butterfly 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 extermigated (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.]
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!
Fires can be devastating. Dried brush, dead weeds, and stacked firewood can speed a fire closer to your home than anyone wants, and can provide shelter for rats. Well-watered plants are less likely to catch fire. It is all too easy to think it won’t happen to you, but it can. 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.
It may be difficult to imagine frost in California, but 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 against winter sunscald and frost cracks 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, or you defeat the purpose.
Some California winters are wet and others are not. Until regular rains occurs, your plants will still need to be watered, though not nearly as often or as much as during the peak of summer. An inexpensive moisture meter can help you see which plants need more water and which do not.
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.
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 create the perfect growth medium for mold. Sooty mold is common in San Jose, California, 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.
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 household cleaner, such as Lysol, for ten minutes to prevent the spread of disease. They should also be stored upside down or on their edge to prevent water collection and mosquito breeding. I used the staves from a half barrel that fell apart 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.
Longer days of sun
Burst forth fruits and leaves
June is a busy month in the garden. Rising temperatures and strong growth increase the need for irrigation. Sowbugs and other pests seem to be everywhere. Fruits, flowers, and mulch are the name of the game when it comes to June garden chores.
Bees are everywhere you look, collecting pollen and nectar for their families (and pollinating nearly all of our garden crops). If you see a swarm, don’t panic. Swarming bees are surprisingly docile. Their bellies are full of honey and they are simply looking for a new home. Contact your local Bee Guild or Master Gardeners for information on swarm collection. Under no circumstances should honey bee swarms be sprayed with insecticides.
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.
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 also use traps to kill rats. It’s a bit disgusting, but it works.
Fruit drop and fruit thinning
Don't be concerned if your fruit trees suddenly drop a majority of their blossoms or immature fruits. This normal behavior, called June drop or blossom drop, prevents trees from producing more fruit than they can support. To help your trees create the highest quality and best sized fruit, this is the time to thin fruits.
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 mulch breaks down, it adds valuable nutrients to the soil and improves soil structure. Just make sure that mulch is kept away from tree trunks and that it isn’t too thick. Generally speaking, a layer of 3 inches is just right. Too much mulch can interfere with gas exchanges.
If you haven't started already, June is an excellent time to plant those heat-loving cucumbers, peppers, squashes, tomatoes, eggplants, and melons. Also, you can create an ongoing harvest by succession planting radishes, beans, and other determinant crops.
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!
Aerate the soil
Our San Francisco Bay Area soil is heavy clay. This means it can hold on to lots of water and nutrients, but it can be difficult for roots, earthworms, and soil microorganisms. You can hire a professional aerator to come in with their heavy equipment to punch plugs out of your soil. While the machine creates its own soil compaction, the plugs really do make a big difference in soil health. Or, you can do what I do, which is to contact your local tree trimmer and ask for a load of tree trimmings. It won’t be the pretty bagged variety, but it will contain chipped twigs, leaves, stems and branches that can be spread on top of the soil as a mulch that will profoundly improve your soil structure. In 2012, when we bought our home, the soil was more like concrete. Now, thanks to mulches of tree trimmings, my soil is rich and black, loose, and filled with earthworms and beneficial microorganisms. For free.
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 Bee Guild or Master Gardeners to have swarms removed.
Bulbs and 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. Sanitize pruners with a household cleaner, such as Lysol, 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 sure to check apples for codling moth damage.
If you still have a lawn, be sure to water it as early in the morning as possible. 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, burclover, 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. This reduces evaporation and it makes the soil more comfortable for valuable earthworms and microbes.
Mulch and compost
Compost and mulch are two of the best things to add to any landscape. They 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.
Before you start applying fertilizers and fungicides, collect a soil sample and send it out to a lab. [I use the UMass lab, but there are many to choose from]. The information provided in soil test results is invaluable. More often than not, your soil does not need more of all the nutrients found in a bag of fertilizer. It may only need some, or, in my case, it only needed iron because it held an excess of everything else. Simply adding more fertilizer can create nutrient imbalances that make it difficult for plants to absorb what they need. Get a soil test. It’s worth it.
This is the most welcome news of the season in the Bay Area. Nearly all summer growing plants (tomatoes, cucumbers, melons, squash, beans, corn, and peppers) 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. This can be done in tandem with quarantining new plants. 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. In most cases, 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 most gardens. With scorching summers on a not-too-distant horizon, flowers, weeds, and everything else seem to be 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.
It’s planting time!
Temperatures are nearing or have reached the point when gardeners can plant most herbs, leafy greens, and vegetables. Lettuce, arugula, spinach, bok choy, basil, parsley, cilantro, and radishes can be planted every couple of weeks in succession for a continuous harvest until temperatures get too hot.
In warmer regions, potatoes, bush and pole beans, corn, cucumber, summer and winter squash, and tomato seeds can be planted now. Be sure to read packet directions for planting depth, spacing, and sun requirements for the best results. [If you haven't already, email me for a customized planting chart based on your USDA Hardiness Zone.]
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 before fruit is affected.
As flowers begin blooming, you can increase production by removing spent blooms.This works equally well for roses and artichokes. 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. Deadheading can help the plant structurally and it allows for good airflow, as well as stimulate new flower development.
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. Containers and raised beds 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 also use water collected from the shower, as it heats up, to water edibles.
Before you get too excited about planting, take a few minutes to inspect your property for mosquito breeding grounds. Mosquito larvae can grow in as little as one tablespoon of water. Birdbaths, rain barrels, clogged rain gutters, and planter pot saucers can all harbor these pests. Mosquito dunks, also available as granular bits, contain a bacteria, Bacillus thuringiensis israelensis (Bt.i), that is deadly to mosquito larvae but harmless against all other living things. You can also use Bt.i against fungus gnats. Mosquitofish can also be used to reduce mosquito populations.
To add nutrients, reduce weeds, and help retain moisture, nothing beats mulch. Wood chips and aged compost both make excellent mulch. You can request free arborist chips from local tree trimmers. To stop weeds from growing, the mulch should be 4" to 6” thick. I used to recommend a layer of cardboard or newspaper be placed underneath, but then I learned that these materials attract termites and voles. Cardboard also slows gas and water exchanges. Be sure to keep mulch at least 8” away from tree and shrub trunks, to avoid fungal diseases, such as crown rot and butt rot.
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. ALSO, BE ON THE LOOKOUT FOR ORIENTAL FRUIT FLIES. IF EITHER PEST IS SEEN, PLEASE CALL THE PEST HOTLINE AT 1-800-491-1899.
Fennel, rhubarb, and asparagus, as well as fruit and nut trees, provide many years of food production and April is a good time to plant. These plants will take up a good amount of space, so be sure to keep mature sizes in mind.
Plum bud gall mite
As of January 2019, we have a new pest in northern California. Be on the lookout for abnormal growths, or galls, on almond, apricot, plum, pluot, and other fruit and nut trees. These tiny eriophyid mites are only 1/100th of an inch long. If you have a 20x hand lens, you may be able to see them. They can be translucent yellow, pink, white, or purple, with two pairs of legs up near the head. You are more likely to see galls on new shoots and fruit spurs that plants produce in response to these invaders. This new pest threatens tens of thousands of fruit and nut trees in California. If you suspect plum bud gall mites on your trees, please contact your County Extension Office right away.
This is also a good time to replace last year's sticky barriers. The protection from crawling insects that these simple barriers provide cannot be overstated. Sticky barriers block those crawlers (and slugs and snails) from getting up into your fruit and nut trees. This is especially helpful when it comes to ants, which will protect and farm aphids. Over time, the goo dries, making it ineffective. Also, the tape tends to pull away from the trunk, creating an easy trail for pests. Gently remove the old tape, inspect the trunk, and apply a fresh sticky barrier. Just be sure that you do not use painter's tape to create sticky barriers. The moisture from the goo will cause the tape to disintegrate and damage the tree's bark.
As difficult as it may be for gardeners to thin out fruit and young plants, it really is necessary for the optimal growth of the 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. Seedling plants should also be thinned according to seed packets or other reputable information. This allows each plant to reach its full potential and reduces problems with pests and diseases. Rather than pulling seedlings out by the roots, snip them off at soil level. This reduces disruption to the remaining (delicate) root systems and leaves valuable soil microorganisms in place.
Tree Trunk Painting
If you didn’t whitewash your tree trunks (and exposed branches) in March, there is still time to provide this valuable sun protection. Trunks and branches that get too much sun exposure can be damaged, causing the bark to split and peel. This provides pests and diseases with easy access to your trees’ inner workings. A simple mixture of half water and half white interior latex paint is all you need to protect your trees from sunburn this summer.
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, removing them now will save you countless hours of work later on, in the summer.