Susan Littlefield - Horticulturist

Although many parts of the country are still in the grip of winter's cold, the days are getting longer, and gardening season beckons, if distantly. It's time to start planning what to grow and when to plant it! Many of the veggies we grow benefit from an early start indoors. Now is a great time to begin gathering seed starting supplies and equipment so you’ll have everything you need when the proper seed starting time for your climate arrives. Here are some tips to help you have strong, thriving transplants ready for the outdoor garden at the appropriate time.

  1. Start by finding out the average spring frost-free date for your area. Experienced local gardeners, your local Extension Service, or online resources can help you determine the average date of the last spring frost (LFD) in your area. Next, refer to the chart to make a seed starting schedule so that plants will be at an optimum size for transplanting to the garden. Cool season crops like broccoli and cabbage are started early, but can go out into the garden early as well, before the last frost date has arrived. Warmth lovers like tomatoes and peppers need to wait until the danger of frost is past. Melons, cukes, and squash do best with no more than about 4 weeks of indoor growing.
  2. Want someone else to do the figuring? Check out the Seed-Starting Date Calculator from Johnny’s Selected Seeds. Simply enter your last frost date and it will do the figuring for you for a wide range of veggies and flowers.
  3. Some plants don’t tolerate the transplanting easily. Plant seeds of melons, cucumbers, and squash in individual biodegradable coir or peat pots so that you can plant the seedlings, pot and all, without disturbing their roots. Homemade paper pots also work great for these plants.
  4. Most seeds germinate best in warm soil. Placing pots on a heat mat (available from garden stores) is an easy way to provide bottom heat. As soon as you see tiny plants poking through the soil, remove any coverings and move the container off the heat mat to a brightly lit spot.
  5. It’s hard to grow strong seedlings indoors with only natural light, even on a south-facing windowsill. Give them supplemental light from fluorescent grow lights to keep them growing strong. Keep lights on for 16-18 hours a day, not around the clock; plants need a nighttime break for best growth. A timer makes it easy to switch lights on and off on schedule. Mount the fixtures so the bulbs hang just a few inches above the tops of the young plants, raising them gradually as the plants grow taller.
  6. Brush your hands gently across the tops of your seedlings every day once they are a couple of inches tall. This little bit of regular movement will help seedlings develop sturdy stems. Or you can set a fan to blow gently across your young plants. The increased air movement will also lessen the likelihood of disease problems.
  7. Be sure to harden off your seedlings before you set them outside. This means gradually accustoming the plants to outdoor light and temperatures over the period of 7-10 days. Set plants out for just a couple of hours in a shady, protected spot for starters; then keep them out for increasingly longer periods of time in more and more exposed locations. Your young plants will then be ready to take off growing when they're planted out in the garden.
  8. Some kinds of plants do best when their seeds are sown directly in the garden. Peas, beans, spinach, corn, root crops such as beets, turnips, radishes, and carrots, and herbs like dill and cilantro generally do best when their seeds are planted where they are to grow directly in the outdoor garden.

Click here to Download Seed Starting Tips

Start seeds 8-10 weeks before last spring frost (LFD)

Start seeds 6-8 weeks before last spring frost (LFD)

Start seeds 4-6 weeks before last spring frost (LFD)

Start seeds 2 weeks before last spring frost (LFD)

Direct sow in garden

Onions: Transplant outside 4 weeks before LFD

*Kale: Transplant outside 2-4 weeks before LFD

*Lettuce: Transplant outside 2-3 weeks before LFD

*Cabbage: Transplant outside 2-3 weeks before LFD

Broccoli: Transplant outside 2 weeks before LFD

Peppers: Transplant outside 2 weeks after LFD

Tomatoes: Transplant outside 1-2 weeks after LFD

*Basil: Transplant outside 1 week after LFD

*Cucumber: Transplant outside 1-2 weeks after LFD

*Zucchini: Transplant outside 1-2 weeks after LFD

*Melon: TranspPlant outside 2 weeks after LFD

*Squash and Pumpkins: Transplant outside 2 weeks after LFD

Spinach: As soon as soil can be worked; approx. 8 weeks before last spring frost (LFD)

Peas: 4-5 weeks before LFD

Beets, Carrots, Radishes, Turnips: 4 weeks before LFD

Cilantro: LFD

Dill: LFD

Beans: LFD or later

Sweet Corn: LFD or later

* Seeds of these crops can also be sown directly in the garden at the transplanting date or later. Starting seeds earlier indoors will give you an earlier harvest.

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