Seasonal Gardening Tips
A few easy tips on how to take care of your school garden through the seasons.
Spring: March - May
Spring in the school garden is a great time to start observing seasonal changes. Days are getting longer, soils are warming, and buds are breaking!
Phenology is the study of observing and recording these seasonal changes. When do the apple trees start blooming? When is the first time you see a Western Bluebird? When do the monarch butterflies visit the milkweed in your garden? Consider creating Phenology Wheels with your students, where each child logs their seasonal observations, and then highlights a couple of these observations every month on their wheel.
A note about protecting pollinator habitat
Spring is here! A time when warmer weather may coax us to start ‘tidying’ up the garden...but pollinators still need this critical habitat!
In the early Spring chrysalides still cling to last season’s dried standing plant material. While you may begin to see bumble bees and ground-nesting bees emerge as flowering trees and shrubs burst into bloom, they still need cover during chilly nights and heavy Spring showers. While mining bees, mason bees, carpenter bees, and bumble bees may be out and about by early April, other species such as sweat bees are still hiding out, waiting for the warmer days that arrive in May. Meanwhile, last year’s leaf litter is still providing protection for both plants and invertebrates against late-season frosts.
So when is the right time to unleash your green thumbs and reach for the rake? It's usually best to wait to weed your garden until it's consistently above 50°F during the day, to allow any hibernating or growing insects to emerge from the leaf litter and dead stems that they have been living in over the Winter. Mid-to-late April should be the earliest you consider cutting back perennials. Keep in mind that some bees don’t emerge until late May, so the longer you can tolerate your “messy” garden the better.
Turning in your cover crops
There are many ways to turn in your cover crop, but in order to occupy the most hands, simply chop your cover crop plants at the base of their stems—leaving the root ball in the ground to decompose—and then cut up the stems into short 2-4” sections to either leave on the bed or add to your compost.
Seed sowing
March: basil, lettuce, scallions, beets, radishes, cherry tomatoes, slicer tomatoes, paste tomatoes, nasturtiums, flowers, mustard leaves for salad mix
April: lettuce, quinoa, beets, pole beans, bush beans, seasonal flowers, mustard greens for salad mix, broccoli, cabbage, cauliflower
May: cucumber, summer squash, winter squash and pumpkins, scallions, dry and dent corn, amaranth, seasonal flowers, scallions, mustard greens for salad mix, carrots
Plant strawberries in early Spring, after the last frost
Purposefully delaying brassica and cucurbit sowing and planting: It’s so easy to plant out our school gardens in a similar fashion to our home gardens without considering crop timing. Filling your beds with brassicas like kale, broccoli, cabbage, and cauliflower in the late Winter, and cucurbits such as squash, cucumbers, and pumpkins in the early Spring, will lead to a prolific harvest in June and July with no kids present to enjoy them! The sowing recommendations above are considerate to planting these longer season crops in late July or early August for a harvest in the Fall months of October and November. This idea is relevant to more than just brassicas and cucurbits, but should also be applied to any crop with a 70+ day growth cycle.
Planting potatoes
March is a great month to direct plant potato spuds. Potatoes could not be easier to grow! They also do well in containers of any kind—old wheel barrels, garbage cans, large nursery pots, or in a ring of wire fencing. A fun project that captures the child’s imagination is a Potato Tower! If you do build a tower, make sure to place gopher wire at the base. Towers can also dry out, so make sure they get plenty of water.
We'd especially recommend planting Bodega Red Potatoes—an heirloom grown in Sonoma County since the 1940s and now being revived by Slow Food Sonoma County North.
Holding off on planting tomatoes until May
Tomatoes can take quite some time to start producing depending on your climate, so we recommend waiting to plant them until mid to late May for a harvest that’ll be waiting for you and the kids upon your return in August. The warmer your climate (i.e the further East your are located in Sonoma County), the later you can plant them to ensure a longer harvest period well into the Fall months. Delaying your planting will also ensure your seedlings won’t suffer from those late April frosts. events!
Summer: June - August
Weeding
The weeds that are growing right now are tenacious, and are robbing your plants of water and nutrients. Prevent them from growing, flowering, and setting seed.
Watering
Check your irrigation system for any leaks or breaks, especially if you have droopy plants by mid-morning.
Keeping an eye out for pests
Keep any eye out for earwigs. They chew large holes in tender vegetation and ripening tree fruit. They are nocturnal so eat at night and hide under mulch or other damp shady spots during the day. Manage them with homemade traps such as rolled up damp newspaper that you dispose of each evening, or shallow dishes with ¼” of vegetable oil in the bottom.
Keep an eye out for aphids and whiteflies. If you find any, use a strong stream of water to wash them away. Or spray them with a homemade or OMRI-approved commercial soap mixture. Hang yellow sticky traps in your greenhouse to catch adult whiteflies and fungus gnats.
Seed sowing
July: leeks, fennel, seasonal flowers
August: broccoli, kale, cauliflower, collards, romanesco
Garden maintenance
Deadhead your flowers. To prolong the bloom time of your annual flowers, remove spent blooms.
Fertilize anything that is a heavy feeder (eg. tomatoes, squash), or that is not growing strongly or has turned pale green. A watering can with a fish emulsion solution should perk everything back up.
Harvesting! Be sure to harvest fruiting crops regularly. If plants such as zucchini or beans are allowed to let their fruit ripen all the way to seed development, you’ll decrease your overall yield.
Fall: September - November
Seed sowing
September: lettuce, spinach, cilantro, scallions, arugula, chervil, chicories, lettuce, pac choi, chard, scallions, tatsoi, beets, mustard greens for salad mix
October: spinach, mustard greens for salad mix, beets, carrots, cilantro, radishes, turnips (Japanese White turnips are juicy and sweet and can be eaten out of hand!), tatsoi, pac choi
November: mustard greens for salad mix
Direct sow fava beans for a crop next April or May. Soak the seeds in water for 12-24 hours before sowing for quicker germination.
Fall is also a good time to sow annual flower seeds. Sow in cleared beds and hand water gently until there are regular Winter rains. Seed species that are beautiful and germinate easily are California poppies, yellow mustard, and crimson clover. You can also sow a California native wildflower mix!
Planting
Plant edible perennials such as fruit trees, berry canes, and bushes. Harmony Farm Supply & Nursery usually has a good selection—choose varieties that ripen in the Fall rather than through the Summer. Before planting anymore cane berries (raspberries and blackberries), make sure to also prune back any canes that had fruit on them this past season to keep the patch tidy.
It’s also time to plant Spring flowering bulbs.
Sowing cover crops
Consider growing a cover crop to add organic matter and Nitrogen to your soil. Good choices for raised beds or small garden plots are bell beans, vetch, and field peas. You can also throw in some crimson clover because it is pretty and adds diversity. Harmony Farm Supply & Nursery and Le Ballister's have a great supply of bulk cover crop seeds. The seed is not very expensive so the kids can at last throw seeds by the handfuls into the beds!
Seeds can also be inoculated with rhizobia bacteria which you can buy along with the seed, which facilitates Nitrogen fixation in your soil. As the plants are growing you can observe white nodules on the roots of the legumes, which is the home of the rhizobia bacteria!
Cover crops are also a wonderful habitat for ladybugs in the Spring, so you can plan some lessons around their lifecycle in the garden.
If you have the room, you could plant garlic cloves in November. Garlic needs a very rich bed with lots of compost since it stays in the ground for almost nine months! It’s also best to plant garlic in a bed by itself as you do need to turn off the water as it starts to form heads. It is usually harvested in June, so it is also a bit tricky to pull off in a school garden, but such a fun harvest!
An interesting activity is to weigh the cloves planted, and then to also weigh the cloves harvested. It can be pretty impressive how many pounds you get from your few cloves!
Garden maintenance
Keep after the aphids! Check your veggies—especially your brassicas—often, and use a strong spray of water to clean off aphid colonies. If they recolonize quickly, spray with an organic insecticidal soap.
Keep pathways free of fallen leaves that can become mushy and slippery.
Getting your garden ready for Winter
To protect your soils over Winter, cut back plants at soil level and let the roots decompose. Allow leaf matter to decay on the top of beds building organic matter, or cover beds with a thick layer of rice straw (which has no weed seeds).
Mulch perennials to keep down weeds and maintain soil moisture.
Be prepared for frost by insulating your crops with frost blankets. These blankets not only protect your plants from frost, but generally warm up and optimize their growing environment. Well-hydrated plants handle light frosts better than dehydrated ones, so it’s also good to make sure to keep up with irrigation until the Winter rains really set in.
Once the rainy season has begun, remove the batteries from your irrigation timers and store the timers in a dry place over the Winter. If possible, also remove the drip tube/tape from your beds and store until next Spring. This will make it last longer and make your Spring bed prep much easier. Winter can also be a great time to clean and sharpen your tools, and organize your tool shed.
Tips for native habitat garden maintenance
With the rain and cooler weather, Fall is the perfect time of year to plant native herbaceous perennials and shrubs, and sow annual wildflower seeds in your habitat garden. Click here for a list of native plant nurseries in Sonoma County, or check out our Network Map.
Mark the location of plants that have gone or are going dormant (such as milkweed) with stakes or flags to protect the area.
Lightly top dress your garden with compost to improve soil structure and support a healthy soil food web.
Add a few inches of wood bark mulch over the compost to help suppress weeds and hold water in the soil.
If it’s not raining, water your habitat garden deeply every 1-2 weeks. Specific watering needs will depend on your plants, soil, rain, and sunlight, but generally natives require less frequent, deeper waterings that encourage their roots to grow deep and expand.
Try letting things go a little wild! Let flowers go to seed to provide food for birds, and leave dead leaves and stalks to shelter over-wintering insects.
Consider a life-cycle approach by creating and leaving spaces for insects, pollinators, and birds to hibernate, nest, and reproduce. This can mean leaving some areas free of mulch for ground-nesting insects, dispersing bundles of hollow stems as shelter and habitat for cavity nesting bees (making sure to refresh the stems in “bee hotels” annually), and providing caterpillar pupation sites under trees using a fallen log or leaf litter. It’s also good to ensure your garden has spaces with year-round protective cover for birds and small wildlife using evergreen trees or shrubs, logs, rocks, or brush piles.
Check out more Habitat Gardening Tips from the California Native Plant Society
Seed sowing
January: lettuce, chicories, onions, parsley, cilantro, chard, scallions, kale, collards, spinach, tatsoi
February: sugar snap peas, spinach, lettuce, kale, leeks, radishes, turnips, mustard leaves for salad mix, seasonal flowers, sweet peppers, shishito peppers, hot peppers
You can also plant perennial asparagus
Winter: December - February
Purchasing seed and crop planning
Winter is a wonderful time to look at seed catalogues and dream about the garden. There are some fantastic small organic seed companies in Sonoma County like Bohemian Seeds which is a run by a West county farming collective. Other companies with locally-adapted, organic, and open-pollinated varieties include:
*Please note that Baker Creek is under scrutiny for questionable and non-culturally sensitive practices.
Seed companies will sometimes share last years’ catalogues with you which you can share with students. Save for rainy days and let students create collages of their dream gardens!