by Connie Oswald Stofko
You can get a head start on gardening in Western New York by sowing seeds for cool weather vegetables such as onions, endive and cabbage.
In this article, Patti Jablonski-Dopkin, general manager of Urban Roots Cooperative Garden Market, 428 Rhode Island St., Buffalo, lays out the details on starting cool weather vegetables from seed.
Some cool weather vegetables can be started inside now–or soon–depending on the last frost date in your area. Other seeds are sown directly outside.
As their name implies, cool weather vegetables can withstand cooler temperatures in the air and soil. That means you can transplant cool weather seedlings outside weeks earlier than you can for tender vegetables, such as tomatoes and peppers.
Urban Roots carries seeds from Botanical Interests and Seed Savers Exchange.
“We love the germination rate of both these companies,” Jablonski-Dopkin said. “Botanical Interests has a wealth of information inside and outside of their seed packets, and we support Seed Savers Exchange’s mission to preserve crop diversity by collecting, growing and sharing heirloom seeds.”
When can you start seeds?
When you can start seeds depends on the kind of seed, but it also depends on the average last frost date in your area.
The instructions on the seed packet will tell you to start seeds a certain number of weeks before your last frost date. If you start too late, you may lose some growing time in spring, which means your cool weather vegetable may struggle in the summer heat.
Starting too early can be just as bad. Your seedlings may become spindly and weak before the weather allows you to transplant them outside.
The average last frost date in the Buffalo area is May 10 -15, said Jablonski-Dopkin. But that’s just an average.
“You know our Buffalo springs,” she said. “Since I’ve been at Urban Roots, I’ve had two Mother’s Days when it snowed.”
And even if the temperatures are right for your seedlings, you may have to postpone planting if the soil is too wet.
To deal with all the vagaries of weather, Jablonski-Dopkin suggests starting seeds in two batches a couple of weeks apart.
Start seeds inside or out? When to transplant?
There are two things to know about starting cool weather vegetables from seed. The first is whether you should start them indoors. The second is whether they are hardy or semi-hardy.
There are some cool weather vegetables that do better started indoors and others that should be directly sown outside into your garden, Jablonski-Dopkin said. You can see the list below.
Whether the vegetable is hardy or semi-hardy will indicate when you should transplant seedlings outside, or if you are direct sowing, when you can plant the seeds outside.
Hardy vegetable seedlings need the soil and air temperature to be at 40 degrees Fahrenheit, while semi-hardy seedlings need temperatures to be a bit warmer, between 40 and 50 degrees, Jablonski-Dopkin said.
Look at the weather forecast, too. If there are predictions of a hard frost, you may want to wait a few days before planting. If your crop is already outside when you get a warning of a hard frost, be prepared to cover your plants with cloths or milk jugs.
Don’t forget to harden off your seedlings before you transplant them outside. About a week before you plan to transplant, set the seedlings outside for a short time to get them used to the bright light and cooler temperatures out there. Each day, set them outside a little bit longer.
Bonus tip: You don’t have to use all the seeds in a packet right now. You can save some for a second crop of cool weather vegetables later this year or for next spring.
Start indoors
Hardy
Sow seeds this number of weeks before your average last frost date
- Broccoli–4 to 6 weeks
- Kale–4 to 6 weeks
- Cabbage—6 to 8 weeks
- Collards—4 to 6 weeks
- Endive—8 to 10 weeks
- Onion—8 to 10 weeks
Semi-Hardy
- Cauliflower—4 to 6 weeks
Direct Sown
Sow seeds outdoors this number of weeks before your average last frost date
Hardy
- Kohlrabi—4 to 6 weeks
- Peas—4 to 6 weeks
- Spinach—4 to 6 weeks
Semi-Hardy
- Beets—2 to 4 weeks
- Carrots—2 to 4 weeks
- Lettuce—2 to 4 weeks
- Swiss chard—2 to 4 weeks
- Turnips—2 to 4 weeks
Potatoes–4 to 6 weeks before your average last frost date. Note: Seed potatoes are whole potatoes that have been checked for fungal issues. You cut the potato up with an eye on each section and sow directly. Seed potatoes will be available at Urban Roots in mid-March or April, weather dependent.
Thanks, Connie. They are actually seeds that I saved from the tomatoes! Your suggestion of starting four to six weeks before planting outside helps. This also allows me to ‘stagger’ my plantings to reap the harvest over time and not all at once.
Hi Judy, check the seed packet. It will suggest sowing inside four to six weeks before transplanting outside, or something close to that. When should you transplant outside? See a discussion on that topic in this article. The discussion will be about halfway through the article, under “Wait until after last frost — or longer — for these plants.”
Hi Connie,
When would you suggest starting cherry tomato seeds inside to be transplanted outside once the frost is done?