Starting Vegetable Seeds at Home

February 15, 2021

By Rick Bogusch, Kathleen Kennedy

Bridge Gardens

Vegetable Garden with Rick series

The Trust is offering a series of monthly videos to share tips and techniques on growing vegetables for the home gardener. This is our first video in our Vegetable Garden with Rick series, featuring Rick Bogusch, Garden Director at Bridge Gardens. 

Future videos will include “Getting the Vegetable Garden Started Outdoors” (Available March 15) and “Compost and Soil Health” (Available April 15.) The videos will be available monthly on the Trust’s blog at

Notes about Starting Seeds, by Rick Bogusch

  • Some seeds are best sown directly into the garden, including carrots, beets, spinach, arugula, cilantro, kale, chard, leaf lettuce and radish.
  • I usually sow the following indoors: artichokes, broccoli, cabbage, cauliflower, tomatoes, peppers and eggplants.
  • Use a soil-less mix that includes vermiculite and perlite.
  • Seeding supplies include cell trays, a watering tray underneath, and a plastic hood to keep moisture in as appropriate for the seed. A heat mat will greatly enhance early germination for many seeds, and an adjustable overhead grow light is very useful. However, you can also start seeds in a sunny windowsill. These supplies can be found online, or at most garden centers, such as Johnny’s Selected Seeds and Fowler’s Garden Center. I bought by grow lights from Amazon and they are the iPower brand.
  • Cool weather crops can be started as early as late February. Vegetables that need warmer weather, like tomatoes, peppers and eggplants, should be started in early to mid-April.
  • You may plant 1 seed per cell or from 2-5, or even a pinch, depending on the seed and the size of the cell pack.
  • Water your seeds/seedlings from below rather than pouring water on top of soil so as not to disturb the seeds.
  • Thin after first true leaves appear, 1-2 plants per cell, depending on its size.
  • When outdoor temps are above 50 degrees, put plants outside and bring in at night if temps fall below 40 degrees. Tomatoes, peppers and eggplants do not like night temps below 50 degrees.
  • Never place in direct sun in the beginning. Acclimate to full sun gradually by placing in shade, then partial sun, then full sun – over the course of at least 3 days.
  • Fertilize with half-strength fish fertilizer every 2 weeks after true leaves have appeared.
  • Plant outdoors in the garden when temps are in the 40’s at night, 50’s for tomatoes, peppers and eggplants.

For tomatoes, peppers, eggplants, and warm weather crops:

  • I usually plant 2-3 seeds per cell and thin later.
  • Bottom heat is a must for these seeds.
  • Start seeds in early to mid-April.
  • When seedlings are 6-8 weeks old, and after true leaves emerge, (plants should be about 4-6” tall) move these seedlings outdoors into the garden.
  • Be prepared to give seedlings extra care in the garden. For the first week, water every day if necessary, to ensure they don’t dry out. Continue until plants grow and show vigor.
  • Fertilize plants with a liquid fertilizer if they look weak and are languishing.
  • Seedlings can also be up potted to produce larger plants before planting outdoors in the garden.
  • Don’t grow too many tomatoes. Along with eggplants, tomatoes should be 2 feet apart and in rows 3 feet apart to provide for air circulation that will discourage disease.
  • Peppers can be spaced more closely in the garden, 1 foot apart, in rows at least 2 feet apart.

Seeding Head lettuce

  • There are two kinds of lettuce seed: conventional and pelleted. Pelleted seed are coated with clay and are little round balls. They are easier to space in cell packs and garden rows than conventional seed because they’re easier to handle. However, pelleted seeds require constant moisture during germination.
  • Use 2 pelleted seeds per cell and thin to 1 later, maybe after planting in garden and both plants have rooted in.
  • For conventional seed, make 2 small indentations in the soil of the cell and place just a few seeds in each indentation, cover lightly with potting soil. I thin seedlings in stages down to 2 plants per cell for planting in the garden, then remove one of those plants once they are established.
  • Head lettuce can be started with or without bottom heat, bottom heat will speed germination.
  • Lettuce likes it cool, so move seedlings outside during the day, making sure they get used to full sun gradually. Bring in at night if temps fall below 40 degrees.
  • Once it’s late April and early May, you can start lettuce outdoors directly in the garden, just make sure to water daily until germination.
  • Space plants 8-12” apart in the garden. To get perfect heads of lettuce, make sure to thin plants to one plant per spot.
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