With all the hustle and bustle of the holiday season, it is easy to put aside garden tasks for another time. We need to rest when we can, too, just as our garden plants do each winter. But December is an excellent time to prevent future problems in the landscape. With just a little bit of effort now, we can have bigger harvests and healthier plants next summer.
Bare root planting
December is an excellent time to install bare root plants in California and other warmer regions. Any of these bare root plants can be planted in December:
Occasional rains will help keep compost piles moist, but remember to turn your compost pile to incorporate the oxygen needed by helpful microorganisms. You may need to cover your compost pile during heavy rains to prevent losing all those valuable nutrients
You can protect your crops by using the USDA Hardiness Map to determine your planting zone and learning when to expect frost to occur. I’m in Zone 9b, which means my first and last frost dates are November 15 and March 15. For plants that may be damaged by frost, you can protect them by draping sheets, tarps, or other light fabric over and around them using poles and string. Do not allow the fabric to touch the plants. Umbrellas and old fashioned (not LED) Christmas lights can also provide some protection. Potted plants can be brought indoors or closer to protective structures. And be sure to water frost sensitive plants. Damp soil holds more heat than dry soil. Also, mulch can stabilize below ground temperatures. If frost damage does occur, resist the urge to clip away the damaged bits - they create a barrier against further frost damage. If it looks really hideous, leave it covered
Garden bed care
As many annuals end their lifecycle, be sure to remove them from the garden bed by cutting them off at soil level. This allows valuable soil microorganisms the time they need to migrate to another plant and the roots will add nutrients to the soil as they decompose. Adding aboveground plant debris to the compost pile not only creates nutrient-rich compost, but it interrupts the lifecycle of many garden pests and diseases. If plant materials are already diseased, they should be thrown in the trash.
Holiday plant care
Poinsettias, Christmas trees, Christmas cactus, amaryllis, and many other holiday plants find their way into our homes in December. Most of these plants prefer cooler temperatures and higher humidity than our homes can provide. Keeping plants away from heater vents and misting them occasionally will help. Also, avoid overwatering.
Winter irrigation is largely dependent on the weather. December is a good time to turn off the sprinklers and monitor the soil with a moisture meter. Cooler temperatures mean slower growth but some water is still needed. Also, if an area becomes saturated with water, avoid walking on it. This prevents soil compaction.
If a tree branch is torn by heavy winds, you can help it heal by cutting the wound to make it a flat surface, close to the trunk, but not cutting into the branch collar. You do not need to paint the wound. Instead, allow the tree to protect itself. It will grow a callus over the area. You may, later on, need to provide the callus with sunburn protection. These other tips will also help your trees stay healthy this winter:
With just a little care now, you can be sure your garden will get through winter for a better spring to come.
Happy holidays, fellow gardeners!
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 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.
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 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. Garden tools should be cleaned, sharpened, and oiled before damp weather sets in.
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.
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.
Fires can be devastating. Dried brush, dead weeds, and stacked firewood can speed a fire closer to your home than anyone wants. 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.
Cooler temperatures may reduce the number of pests in your garden and landscape, but imported cabbageworms, brown marmorated stink bugs, and Harlequin bugs 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.]
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.
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.
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!
Frosted lawns and trees
Cracking crystals in birdbaths
Hunker down in sleep
As holiday decorations are put away and life returns to a chilly normal, January provides some surprising opportunities to benefit your garden with little effort on your part.
If you are like me and enjoy the flavor of fresh asparagus in the spring, this is the time to plant. Before planting asparagus crowns, be sure to select a long term site. My mother discovered a patch of asparagus on her Upstate New York property that had been growing continuously for nearly 100 years! Your asparagus plants will need 2-3 years to get established, but then you will be set for a lifetime of delicious spring stalks that taste better than anything you can find in a supermarket.
Bare root trees
January is also a good time to plant bare root fruit trees. Bare root trees should be planted as soon as they arrive to avoid letting them dry out. When shopping for bare root trees, be sure to inspect the root system and reject plants with knotted or diseased roots. If a tree speaks to you and you simply must have it, cut off any damaged or diseased roots with a sharp tool, cleaning between each cut, and cross your fingers. Contrary to popular belief, there is no need to add special soil amendments to the bottom of the hole before planting.
If you decorated a Christmas tree this past year, rather than kicking it to the curb, you may want to put it to work in your garden. Keep in mind, however, it may not be organic and it might harbor pests. It's your call. Personally, I remove all the lights, decorations and tinsel and let nature takes its course.
Initially, your tree will provide shelter for small birds. I once had a goldfinch escape a hawk for 40 minutes, hopping around the interior of my discarded tree. The hawk finally gave up and the goldfinch survived. Contrary to popular belief, pine boughs do not acidify soil.
While colder temperatures may have slowed the rate at which your compost pile breaks down, you can still keep adding to it from your kitchen and yard scraps. This goldmine of nutrients provides countless benefits to your soil and the environment. Just remember to turn it occasionally. You may also want to protect the pile from leaching rain with a tarp.
January is also the time when seed and plant catalogs start arriving in the mail. Rather than going hog wild and buying everything that looks good in the photos, ask yourself what you want from your garden, how much time you have to invest, and what worked well (and what didn’t) over the past year. The job of those catalogs is to sell seeds. Your job, as a gardener, is to consider your soil, microclimate, and personal preferences. Does an existing bed need updating? Do you want to try your hand at something new? You can use garden themes to help with plant selection:
As you design this year's gardens, try to keep them accessible to all your helpers and visitors.
If you have established trees and roses, January is an excellent time for pruning. The only exception is apricot, which must be pruned in summer to avoid eutypa dieback. Each species of tree has characteristics that make different methods of pruning more effective than others. Proper tree training can increase production while reducing pest and disease problems. This is also the time to start collecting scions for grafting.
Pest and disease prevention
While most pests are gone or dormant in winter, January is a good time to prevent spring infestations and infections with horticultural oil, fixed copper, Bt, and other treatments. If you had problems with soft scale last year, horticultural oil will do the trick. If your nectarines showed signs of peach leaf curl, protect them with fixed copper. Applying Bt in winter can prevent many fungal diseases later in the year. Some of those treatments should be applied when a plant is in full dormancy while others should be applied during the delayed dormant period, so it is good to know the difference. Also, be careful about mixing products. Applying them too close together can cause more harm than good.
In most places, January soil is best left alone. Wet or frozen, this is not the time to be digging. Your plants and soil will benefit from mulch, however. Mulch holds the day’s warmth and improves the soil for spring plantings and new growth. Just be sure that mulch stays several inches away from trunks and stems, to prevent fungal disease and pest infestations.
January is also the perfect time to clean, repair, and sharpen your garden tools. Start by cleaning them with bathroom disinfectant to kill off pathogens and remove debris. Then, use a wood file, rasp, or tool sharpener to bring back that clean edge. Finally, apply some mineral oil to prevent rust. Your tools will last longer and work better with just a little bit of care. This is also a good time to clean your pots in preparation for spring. Be sure to wash all your pots and unused containers with a household cleaner, such as Lysol, to prevent the spread of disease.
Start your gardening year with clean, sharpened tools, a little preventive work, and a plan for a successful growing season! Happy New Year!