Depending on where you live, the growing season can be limited, and it can be challenging to extend it. Know which crops are cold tolerant and which need warmth to thrive. Know how to protect your seeds and seedlings from unexpected temperatures. This calendar gives planting dates for both spring and fall in Climate Zone 5b which covers most of northern Illinois as well many other areas in the U.S.
Know WHEN to plant & harvest
The U.S. has 13 “climate zones” (plant hardiness zones.) Find your climate zone in the Map of U.S. Climate Zones. To learn more about how climate zones work and how to use planting calendars go to our blog post What are climate zones?
Average frost dates. Each climate zone has an average first frost date in spring and average last frost date in fall, which determines the length of the growing season. An exact frost date is unpredictable due to climate change. The LAST average frost date is May 10 to 15 in climate zone 5b. The FIRST average frost date is October 10 to 15.
Most Chicago gardeners are in climate 6a. We don’t have a planting calendar for climate zone 6a which is somewhat warmer and applies to most of the city of Chicago due to the “lake effect.” Lake Michigan influences the climate of Chicago and most of northeastern Illinois. The large thermal mass of the lake tends to moderate temperatures, causing cooler summers and warmer winters.
We prefer that Oak Park gardeners follow our zone 5b planting calendar even though Oak Park is officially in zone 6a. River Forest (just west of Oak Park is officially in zone 5b.
Beginners should plant at the warmer part of a planting period. The Deep Roots team likes to be conservative about when to plant to make growing less risky for beginners. But we also want you to learn the tools to protect your garden from unexpected cold temperatures and heat waves.
Experienced gardeners living in zone 6a can take advantage of its longer frost-free growing season. Use our zone 5a planting calendar in this post as a reference point. The zone 6a spring planting dates are 2 weeks earlier and the fall planting dates are 2 weeks later.
Climate change has made the safe planting date a moving target. It’s unpredictable. It’s helpful to know the lowest safe temperature for each crop. Many crops can be planted before the last frost date. Some crops are more sensitive to cold than others. Know what is the lowest temperature a crop can tolerate, especially at night. Some crops are very sensitive to temperature and some are less sensitive. Learn more in our temperature tolerances blog post,
Raised beds are well-suited for season extension because they can be easily covered and protected from the elements.Raised beds have become increasingly popular in recent years due to their many benefits, such as better drainage, improved soil quality, and easier access for gardeners.
Mini-planting calendars for 9 plant groups
These are general guidelines based on averages. The best planting dates can vary based on specific local weather patterns and the particular variety of each vegetable. Always check seed packets for specific planting information. Also, the temperatures given are in Fahrenheit. The temperature tolerance for specific veggies in our mini-calendars is in our blog post Veggie Temperature Tolerance.
Our planting calendar post is divided into 9 planting groups, each with its own mini-chart below. A few important tips are listed under each mini-chart. We hope to provide more tips on each veggie soon in a new post. Below are the veggies in each planting calendar mini-chart:
Brassicas (broccolini, Brussel sprouts, cabbage, cauliflower, collards, kale, kohlrabi)
Cucurbits (cucumbers, cantaloupe, summer squash, winter squash, zucchini, watermelon)
Flowers (cosmos, marigolds, nasturtiums, zinnias)
Fruiting plants (eggplant, sweet peppers, hot peppers, cherry tomatoes, Roma tomatoes, heirloom tomatoes)
Greens (salad amaranth, Swiss chard, Bibb lettuce, New Zealand spinach, spinach, Tatsoi)
Herbs (basil, cilantro, dill, oregano, sage, parsley)
Legumes (bush/pole beans, fava beans, snap peas, snow peas, shell peas)
Root crops (beets, carrots, garlic, green onions, parsnips, radishes)
Corn (sweet corn)
Seeds or seedlings? Plant seeds or seedlings for kale. Plant seedlings for brussel sprouts, cabbage, cauliflower, collards. Plant seeds for kohlrabi.
Pests and diseases: Spray weekly with BT (Bacillus Thuringensis) to repel insects.
Fungal Diseases: There are many fungal diseases. For example, “club root” attacks broccoli and broccolini roots and stunts plant growth. It is very tricky to prevent and manage since the disease stays in the soil for many years. Another example is “stem rot” which can be stopped with a biofungicide/bactericide spray.
Broccolini: A fast growing, delicious crop that can replace broccoli.
Brussel Sprouts: Needs meticulous crop protection over a long season.
Cabbage: Choose short season, compact cabbages for success.
Kale: Is a superfood. Plant early and mid-season for abundant crops.
Kohlrabi: A delicious root crop. Plant early and mid-season.
Seeds or seedlings? Plant either seeds or seedlings for all cultivars. Beginners should plant seedlings.
Pests and diseases: Spray all Curcubits weekly with organic biofungicide for powdery mildew prevention and management.
Cucumber: Pick hidden cucumbers before they get over-ripe and turn yellow which can signal the plant to stop or slow fruit production.
Zucchini: Although they are huge plants with enormous leaves, they don’t need a trellis. Planting in large containers or in a separate bed is best. Many gardeners prefer to pick zucchinis at 12” long or less.
Trellis is needed for cucumbers, summer squash, and winter squash. View this video with a wide range of trellis designs you can buy or make yourself. Cucurbits need a very sturdy and strong trellis. Squash and melons can also grow on the ground or on a lawn without hurting the grass.
Seeds or seedlings? Plant either seeds or seedlings for all cultivars – eggplants, peppers, and tomatoes.
Placement: Alternate peppers, small marigolds, and basil in a bed. Place kale, lettuce and chard on the south side of the tomatoes if there is room.
Tomatoes: Indeterminate tomatoes need a tall stake since they never stop growing. Determinate tomatoes are smaller and produce all fruit at once. Plant seedlings deep so part of the stem is under soil. Don’t water very much, other than at the beginning. Deep water every few days. View a video on tomato pruning. View our blog post on Tomato Growing Tips. Buy tomato seedlings from the Oak Park Tomato Lady and read her growing tips.
Pests & diseases: Plant disease resistant cultivars. Prune the lower leaves up to 10” to prevent fungal spores from splashing upwards. Dip your tool in alcohol as you prune diseased leaves. View tomato disease prevention post.
Eggplant: Plant disease resistant cultivars. Plant mini-eggplant seedlings in midsummer for a fall crop.
Season extension. A lightweight “floating row cover” might provide 2ºF of frost protection, whereas a heavy-weight row cover might provide as much as 6ºF to 10ºF of frost protection. In the spring, when transplants are small, row cover can often be simply draped over plants without a frame.
Seeds or seedlings? Plant either seeds or seedlings for chard, lettuce, New Zealand spinach and tatsoi. Plant seeds for spinach and amaranth.
Pests: Spray weekly with Neem Oil. Use Pyrethrum on alternative weeks
Spinach: Plant seeds November 15 to 30 for March germination. Spinach will begin to flower (called “bolting”) as soon as spring days begin to lengthen. The response comes when days are longer than 14 hours and temperatures creep above 75 degrees F. (23 C.) In Chicago area 14-hour days start on May1.
Tatsoi: Versatile, nutritious oriental greens.
Lettuce: Don't plant too much at once. Do 2-3 small plantings of leaf lettuce and radishes 7 to 10 days apart in early spring, with another planting in the fall.
New Zealand spinach and amaranth salad: Summer substitutes for spinach. Heat tolerant.
Seeds or seedlings? Plant either seeds or seedlings for basil, cilantro, oregano, sage and parsley. Plant seeds for dill at intervals for big harvest.
Basil: Is a must for pest protection. Plant next to tomatoes.
Oregano: Is an excellent ground cover for strawberry and asparagus. It is a cold tolerant perennial that comes back year after year
Sage: Is a perennial that needs protection over winter. Place a layer of straw around it.
Dill: Choose a spot protected from high winds because the tall, hollow stalks can easily blow over if you don’t stake them. Sow several batches of seeds a week apart.
Cilantro and dill: Plant in spring and again in August.
Seeds or seedlings? Plant all peas and beans from seed.
Peas: To speed germination, soak seeds in water overnight before planting. Peas come in two heights – bush peas and climbing peas. Provide a trellis since all peas need support. Bush peas are only 2 to 3 feet tall. Climbing peas may reach 6 to 8 feet tall and they need a sturdy trellis or a pole.
Bush beans and pole beans: Plant weekly for successive summer crops.
Fava beans: They grow as rigid, upright plants from 2 to 5 feet tall and often require staking as they mature. Plant in late spring.
Pole beans: Are vines that keep growing all season and need a tall trellis.
Bush beans grow compactly (reaching about two-feet tall) and do not require extra support from a structure like a trellis.
Trellis designs: We like this video with a wide range of trellis designs you can buy or make yourself that work well for climbing beans. Use the same trellis for peas and beans. Peas are a cold weather crop for spring and fall. Beans are warm season crop.
Seeds or seedlings? Plant all root crops from seed.
Harvesting: Find one whose top is sticking out of the soil. if it pulls out easily it is ready to harvest. They will not be ready all at the same time.
Beets: Thin early for baby beets and harvest the rest when full size.
Carrots: Over winter in the bed to optimize sweetness. Very tiny seeds are tricky to plant. Keep seeds and new sprouts moist constantly. Great tips in video How to sow carrot seeds that includes protecting seeds with a board until they germinate.
Garlic: Plant in mid-October and harvest in mid-July. Cut off “garlic scapes” (curved white bulbs on a long stem).
Green onions keep renewing as they are harvested. If harvesting, use only green tops over winter and grow again in spring.
Parsnip: Over-winter in the bed to optimize sweetness.
Radish: Fastest crop to grow to maturity
Seeds or seedlings: Plant from seed.
Staking: Support with an 8-foot sturdy pole secured properly.
Pollination: Need at least 10 corn plants to pollinate each other.
Seeds or seedlings? Plant seeds or seedlings for cosmos, marigolds, nasturtiums and zinnias.
Pests and diseases: If you need help, contact Chicago Botanic Garden plant information service: plantinfo[at]chicagobotanic.org and (847) 835-0972.
Cosmos: Plant at raised bed corners. Cosmos attracts beneficial insects that feed on crop pests – everything from tiny parasitizing wasps to aphid-hungry hoverflies.
Marigolds: Are ranked number one as the best flowers to plant in the vegetable garden. Plant at edges of your raised bed and between tomatoes & peppers. They continue to flower into the fall.
Nasturtiums: Have edible flowers, leaves and stems with a tangy flavor. Plant at sides of the bed and prune so it grows only toward the outside of the bed.
Zinnias: Attracts pollinators, especially butterflies. Interplant between vegetables or as a border to attract more pollinators. They lure predator bugs into a fall garden where they eat the pests. Their long bloom season makes them excellent for landscape color in mixed plantings.
