As temperatures start to rise and signs of Spring make their way, it’s time to start planning your gardens and starting some seeds ahead of time. Knowing when to start seeds indoors and/or when to direct seed outdoors after the threat of frost can be intimidating. Factors such as soil temps, sunlight hours, moisture, frost hardy, frost dates, germination and more, all play a role in knowing when to begin certain seeds.
We’ve put together a list of the main garden veggies that most people grow in our area here in southern Ohio (zone 6a). Below, you will find information explaining when to start seeds for a spring harvest, summer harvest and a fall harvest. If you are wanting to harvest beets in October, you will want to know when during the summer to start them!
Spinach: Start sowing as soon as soil can be worked. Usually mid-late March in our zone.
For a fall crop, start sowing mid to late August. If soil Temps are above 85° keep the soil cool by watering it very often, do not let it dry out. You could start another succession end of August. Spinach takes around 45 days to maturity (a little longer in the early spring when Temps are colder during germination). You can continue planting through September. Plant in early October to over winter, for an early spring crop. Floating row covers will add extra protection but the roots will survive winter without protection.
Lettuce: Sow same time as spinach. Lettuce and spinach will germinate in soil Temps as low as 40°. If you’re growing head lettuce, you can begin your seeds in trays indoors, beginning of March or about 3-4 weeks before direct seeding outside. Be sure to harden the plants off (let them experience the outdoors a few hours a day before transplanting). Transplant when the ground is warm enough to work the soil, and after the dangers of heavy freezes. Spinach and Lettuce can handle frost! (Just be sure NOT to touch the leaves until all frost has thawed and leaves have dried in the sun).
Sugar snap peas: Same as lettuce. Peas can definitely handle mild frost. For a fall crop, direct seed late July or early August. Keep the soil very moist! If you plant seeds in the summer, they can easily be scorched in the sun/heat so keeping them watered often is crucial.
Radishes: Sow early to mid April. Keep even moisture throughout growing AND harvest. It will reduce the pithy appearance (splitting) and keep the taste mild. When they get dried out or too hot, they split and become very spicy.
For a fall harvest, plant radishes end of August and be sure to keep the soil very moist. Radishes mature in warm Temps in about 25 days. So plant a few succession for fall harvests. Not recommended to start In trays.
Beets: Direct seed once soil is staying above 45°F. For a continuous supply, sow every 2-3 weeks until about end of August, or about 8 weeks before the threat of a heavy frost. Not recommend to start in trays.
Carrots: Start sowing early April for a summer harvest. Keep the soil moist!!! Carrots do not like to dry out. They take much longer to germinate compared to other root veggies. They can take up to 10-21 days to germinate so its important to keep the soil moist the whole time, and throughout growing. They like deep, loose soil (prevents splitting, and short stubby carrots). Sow carrots through the summer for a fall harvest.
Late summer plantings will winter over well in our area - for a nice early spring harvest. Mulch them with straw, leaf compost or saw dust to help prevent freezing too hard which will make the carrots mushy.
Tomatoes: if you are growing from seed, start no more than 6 weeks before transplanting outdoors. (Unless you have a greenhouse). Tomato seedlings like WARM! Full sunlight or supplemented light from something like a grow light is needed. It’s not recommended to plant outdoors until after mothers day unless you have a way to protect them from late frost threats. The lightest frost will kill a tomato plant.
When starting seeds indoors, if you notice your seedlings getting tall and leggy, it is because they are reaching for the sun. In this case, they need more light. Keep well watered. Heat mats recommended. Be sure to harden them off after mothers day by letting them experience the outdoors/wind a few hours a day for a couple days. Transplant outside end of May.
Peppers: Start indoors late March or early April in 2" trays or 4" pots. Peppers need warm soil. Seed mats recommended. Keep soil moist, at around 80-90° if possible for germination. Once seedlings emerge, Temps only need to be 60-70° to grow. They need full sun or grow lights. Transplant late May after all signs of frost have ended.
Green beans: Sow late may through early July directly in the ground. No need to transplant green beans. You will get a nice harvest planting anywhere in this time frame. Keep soil moist all throughout the germination time period and growing plant.
Winter squash: Direct seed outdoors late may/early June for a bountiful harvest through the fall.
Summer squash/Zucchini: Can be started indoors end of April in 2" cell trays. Transplant about 3-4 weeks later after threats of frost. Plant succession every 2-3 weeks for continuous harvest. I would stop planting seedlings mid summer.
Cucumbers: Direct seed late May or start indoors end of April in 2” cell trays. Transplant them in about 3 weeks. Keep well watered. Not recommended for a fall crop. They can be started as late as end of June, to still get a good summer crop.
I hope this list was helpful! If you don’t see a specific vegetable listed here that you grow, just reach out and we’d be happy to let you know when to start seeds for a spring, summer or fall harvest. Happy planting!
