Written by: Dr. Carole Christopher, SPEC Guiding Elder, Director, Master Gardener
It’s mid November and we are in the middle of the second wave of the COVID-19 pandemic. A lot of people took up food gardening this Spring and I know that gardening is an amazing passion but also has discouraging surprises, especially for new gardeners. I’d like to support people through the disappointments until the passion takes hold.
Hopefully some of my trials and errors over 50 years of vegetable gardening will be reassuring and encouraging. We are all learning all the time.
We used to speak about “Fall Clean Up” – that time when we cleared the garden and ‘put it to bed’ until Spring. We now talk about Fall Garden Maintenance; based on a view of gardening that’s been changing rapidly in the last two decades.
In our mild coastal climate, people are doing year round gardening.
Job Number 1: is not to haul stuff out of the garden but to haul things back into the garden to replenish and protect the soil. There is a world of support below the surface, full of living organisms, from small mammals, worms, and arthropods to the microscopic organisms, to the amazing world of fungi working to make our gardens beautiful and productive.
All this living and decaying organic matter combine into a matrix of exchange that builds soil fertility. We need maintenance practices that feed and support this living matrix. Much damage has been done to soils around the globe by practices aimed at getting the most above the ground while returning the least below. And often what we do in return has been in a form that damages this living matrix. The earth is the resource that feeds us. Let’s return the favour.
The role of soils in the context of climate change. Healthy soils store or sequester carbon. Unhealthy soils yield carbon to the atmosphere. How we grow veggies matters at this level too. So, let’s be specific about how to feed the soil. Soil supplies all the basic needs for a seed to grow into a mature plant – except water and sunlight and (perhaps) fertilizer. What we take out must be replenished. We replenish with organic material such as mulch, compost and humus to nourish the soil.
Some veggie gardeners use only these amendments as vegetables are heavy feeders, others also use fertilizers. BUT there’s a big cautionary note because there’s a tendency to over fertilize which damages the soil and pollutes our water sources.
All the living organisms find their way to our soils if we use practices that support the life cycle of healthy soil. These practices include:
Mulching - covering the soil with organic material to protect the soil over the entire year – except to pull it back briefly in the spring to allow the soil to dry out and warm up.
Composting - what we take must be returned. This is largely the job of compost - home grown or bought.
Leaving roots by cutting plants at the soil level and letting the roots give what’s left of their goodness back into the soil.
What is mulch and how does it benefit the soil?
Mulch is an organic material such as leaves, straw, unused crop foliage or stems or twigs that cover the soil and provide protection. It helps to stabilize soil temperature (which is cooler in the summer and warmer in the winter). It prevents water loss, suppresses weeds and it adds organic matter to the soil. You can ‘chop & drop’ unused foliage of plants that are cut down. Fall leaves are a garden bonanza. You probably have leaves but, if not, walk down a few alleys (in your neighbourhood) and you’ll find leaf bags aplenty and no one will mind if you take them before they’re collected. I used to grind all my leaves – one of my husband’s favourite fall activities is to fire up the leaf grinder and tear through the leaf production of our big red maple.
But I’ve changed my practice and recommend grinding leaves for summer mulch while using whole leaves for winter protection. The fluffier the better as air is being held in the leaf layers as insulation. Pile the leaves several inches, though pull them back slightly from the stem to allow ventilation. Leaves protect the soil from heavy pelting rains that leach nutrients and, as they break down, they are food for the soil organisms. Leaves also make your summer garden water smart by reducing moisture loss. Ground leaves in the summer are easily pulled below the surface as a food source by micro-organisms. Replenish as needed.
Don’t forget to pull the leaves back in early Spring. I neglected this step last spring and lost my early seedlings to a bumper crop of saw bugs or pill bugs hanging out at the very moist surface. I pulled the mulch back and let my next batch of seedlings grow bigger while the soil dried out and the critters burrowed into deeper layers of the soil. The more mature seedlings were sturdy enough to take care of themselves .
What is the role of compost?
Every year we take a lot of organic material and nutrients out of our soils in the form of the vegetables we harvest. Compost puts organic material and some nutrients back. Whether you make your own out of garden and kitchen ‘waste’ that decomposes or you buy it, it’s an important soil amendment.
Whether it’s “hot” or “cold” compost or “chop & drop” foliage right where it was growing, it all decays into something that looks like soil but has different constituents that replenish garden soils. It can be used as a mulch but is generally blended into the top three or four inches of topsoil. Do it gently to disturb the soil as little as possible. Every soil disturbance breaks up the network of organisms, fungi and plants that create this feeding web of life.
Why leave the plant roots?
This is quite a new recommendation based on knowledge that there is a zone of active biological organisms and fungi around the roots that are symbiotically supporting the plant and each other. The plant is also feeding them and leaving the roots will continue to feed the soil even after the above ground plant is removed.
Job Number 2 - protect plants that are tender or small and easily damaged by snow and harsh winter conditions. Again, mulch is a major benefactor in this protection by protecting the roots but some above ground support for small plants is also good.
Take a look at your plants and ask yourself, “Could this plant use some extra support in heavy winds or a snow load?” Depending on the strength of the stem and the size of the plant, often the answer will be Yes. Get some of the smallest garden stakes and cut them to the right size to provide that support. Build a circle of four sticks close to the stem that supports the plant.
I also cover the garden beds that need extra protection with Reemay cloth. It’s lightweight, lets in light and water, and provides insulation for the extra cold times. During periods of severe cold, I put burlap over the tender perennials like Rosemary along with several inches of leaf mulch. You can leave Reemay in place for longer periods but remember to take the burlap off when the cold snap is over. Light doesn’t penetrate the burlap.
NO Fertilizing – The general rule is to stop fertilizing about six weeks before the first frost. Frost dates depend on latitude and elevation and they’re based on averages. Sometimes we’re caught by weather events that fool our calculations. Locally, the first frost typically happens November 11-23 but this year it happened in mid-October. It’s stressful for plants to protect against frost and simultaneously respond to fertilizer so many gardeners stop fertilizers in late August. It’s also important to follow instructions for when and how much to fertilizer in the Spring and during the growing season. Take the time to understand and follow instructions.
To say that we stop fertilizing is not the same as saying that we’re not feeding the soil. Remember that applying compost and mulch is returning organic material and supporting the development of microbial and fungal life but they have low levels of nutrients that stimulate growth.
Most veggie gardeners use an organic fertilizer in Spring and mid summer - but with care to follow instructions. Stop fertilizing in late summer and let your Fall focus be on mulch, compost and other organic material to protect and replenish the soil
Lime – This is a good time to lime your veggie garden beds. Most regional soils are too acidic (pH is too low) for vegetables and adding some lime is a regular maintenance. Some people do this in the Spring but Fall is perhaps better because it does its work in the root zone and it has the winter to work its way down in the soil. Otherwise, the recommendation is to dig it in deeply and remember what I’ve said about soil disturbance and damaging the soil food web. A safe amount without testing is about 1 cup for every 50 square feet. That’s not a lot so measure it and plan how to distribute. Put it on dry soil and rake it in gently.
Soil Tests – Speaking of pH brings up the importance of soil tests because pH is included in such tests and specific recommendations are made for the amount of lime to add, if any. A soil test is helpful and Fall is the best time to do it. It gives us a good picture of the composition of our soils and what may be too low or, just as importantly, too high, and what to do about it. Here’s a quick personal story; about 20 years ago a soil test showed that the ‘little pinch’ of bone meal I was using with every transplanted seedling had accumulated in the soil and was now stunting my plants. The soils expert gave me options for how to remedy the situation and since then I’ve learned that this ‘old habit’ is strongly discouraged by Master Gardeners.
Soils tests are not cheap BUT you only need them every 4-5 years and they can make a big difference in productivity. One of the biggest disappointments of new gardeners is poor soil conditions and not understanding why their plants don’t prosper. Do-it-yourself soil tests are not adequate. If your soil is highly productive and you’re not relying on high dosing chemical fertilizers, perhaps you don’t need a test. If you are relying on chemical fertilizers to get productivity, there may be a slow deterioration that, in time, will exhaust the soil.
It’s not easy to get good and simple information about how to take samples for a soil test so here’s a quick info session: Take 8-10 samples from different spots in your food gardening area. If it’s several raised beds, perhaps take one sample from each. If it’s one large area, spread out and sample several spots. Specifically, to take the sample: take a hand shovel and dig it fully (10-12 inches down) into the soil. Push the soil forward leaving the edge behind the shovel free. Gently remove the shovel leaving the soil pushed back. Take a 1 inch slice along free edge to the depth of the shovel. (That should be about a half cup) Put that into a pail and repeat the process for the remaining samples. Once you’ve collected the samples, stir them together and make sure they’re well mixed. Put it into a plastic bag, label it and deliver it to a soil analysis lab. I use Pacific Soil Analysis in Richmond.
Spring Bulbs and Planting: This is a time to plant bulbs, wildflowers mix, poppies, and perennial flower seeds that need to be exposed to cold before they sprout like Rudbeckia, Columbine, Sedum and perennial sweet pea. Refer to the seed package. Overwintering plants like Kale and collards can be left in the garden. Root crops (beets, carrots) will be fine but it’s good to mulch around their shoulders.
Swiss chard, winter lettuces, mustards, and arugula will like the mulch and in severe weather I cover mine with Reemay cloth. Harvest gently and leave something for the plant. Most overwintering veggies, no matter how bedraggled they look, will bounce back and put on bulk for early harvest. This is also a time when you can divide and give away some crops. Sorrel, chives,perennial onions are examples.
It’s getting late in the season, however you can transplant perennial flowers - Here’s a partial list: Dianthus, Echinacea, Hellebores (shade), Bergenia (shade), Gaillardia, Phlox, Coreopsis, Sedum , Salvia, Lavender, , Rudbekia . Hostas, Heuchera and Grasses can also be moved now.
Nursery plants are selected for seasonal planting. If you like them, they should be fine. Consider amending the soil with compost (not fertilizer) and be sure it’s watered if the soil is dry. You can do some light pruning of roses but wait until later winter for heavy pruning or moving.
Containers – If you can, move them to a more sheltered place, up against the house or under eaves where they’re protected from drenching rains, strong winds and severe cold. Remember, container plants are exposed on all sides. You may want to cover them with Reemay cloth for extra protection in severe weather. Summer annuals and other tender container plants will not survive outside.
Pruning – The pruning season is from November – February, February to early March. However, Fall is generally not the best time to prune for many plants. Pruning is complicated and there are many exceptions to any rules we devise. I suggest an excellent 2018 Vancouver Sun article by Brian Minter who gives lots of specific information about when to prune different plants. https://vancouversun.com/homes/gardening/brian-minter-when-to-prune-or-not-to-prune/ I also recommend Cass Turnbull’s excellent book, A Guide to Pruning that shows pruning cuts, how to make them and tools to use. https://www.goodreads.com/book/show/327689.Cass_Turnbull_s_Guide_to_Pruning. Good pruning can make a world of difference. Bad pruning can do that too. Unless you know how and have the tools or are prepared to study this subject, you might want to consider professional support especially for the big jobs.