The Illinois Extension Master Gardener Help Desk email inboxes have been busy since gardening season has arrived. The early season questions have tapered off with a new batch questions, including sowing summer vegetable seeds or getting those tomato and pepper transplants.
Gardening is weather dependent. The theory is if you base gardening on what is called the average frost free date, plantings or sowing of seed occur before, on, or after that date. Vegetables are grouped by hardiness: very hardy, frost tolerant, tender, and warm-loving. That gives us here in northern Illinois the chance to plant our vegetables for spring, summer and fall gardens, depending on the hardiness of vegetable plants.
Both tomato and pepper transplants go in after the worst of the frosty weather and after the cool days have passed, yet one of these is more tolerant of cooler temperatures than the other. Since they are often bought together, they often get planted at the same time. But, America’s favorite garden vegetable (fruit), can go out to the garden at least 7 to 10 days before the other. If you guessed right, it is the tomato. When you plant tomatoes and peppers at the same time, you can see one of two problems. If you wait until the warmer temperatures for the peppers (warm-loving), you lose up to 14 days of development on the tomato (tender). Plant them together at tomato timing, and the peppers will be chilled and set back before they begin to really grow and develop.
If you have the space and want to try a gardening experiment, plant a pepper with the tomatoes, wait the 7 to 10 days or more then plant another pepper. Even though they are a week or two apart, the earlier one will have a hard time catching the one planted at the later date because it was chilled and set back.
Sowing vegetable seeds follows a similar pattern. At the time you plant those peppers, you can sow those other warm-loving vegetables too. Some of these are easier to remember like all the vine crops – melons, cucumbers, etc. Others are eggplant, okra and lima beans.
Now back to the tender vegetables (like that tomato). There are fewer of these, yet they often are grown in abundance. While you are transplanting the tomatoes, sow those snap beans along with sweet corn and New Zealand spinach.
One of the great things about understanding the growing conditions favored by vegetables is the ability to utilize the garden several times throughout the growing season. For example, once the radishes (frost tolerant) or leaf lettuces (hardy) are done, that same space can be used to sow the first of the snap beans (tender). Snap beans can get a second planting about a few weeks later, for sure. When the beans are done, there is the opportunity to sow the fall or winter seeds. It is always better to plant successive short rows than one long row giving the family fresh beans throughout the summer and not all at once. Usually that is on a 10- to 14-day interval, or as space allows in your garden.
Have gardening questions? Find your local Extension office website to learn how to connect with your local Master Gardener Help Desk.
About the author: Richard Hentschel’s expertise extends across several subject areas with specialties in lawn care, fruit tree production, woody ornamentals, and home and community gardening. During his 45-year career in horticulture and agriculture, Hentschel became a well-known and respected expert for commercial and homeowner audiences, industry organizations, and media. He retired from University of Illinois Extension in April 2022 with nearly 30 years of service as a Horticulture Specialist and Educator in northern Illinois.