Monday, March 5, 2012

Seed Starting and Hardening off For Spring Veggies

If you haven't gotten going already, now's the time to start sowing seeds indoors for your crops like tomatoes and peppers which usually require about 6-8 weeks from sowing to transplanting to the garden.  There's also still time to start some cool season crops like lettuce, cabbage, and cauliflower. For all the above crops, transplanting works well and 65 degrees is within the optimum range for germination soil temperature.  This makes starting the seeds indoors a good way to save some money and get a jump on the growing season.  You can quick start some seeds by soaking them in a shallow container of warm water over night, or by wrapping them in a wet paper towel and enclosing them in  a clear plastic bag for a couple days until you see the first root sprout.
For best results use a sterile growing media, and plug trays or cell packs that keep seedlings separated and thus fungal diseases contained.  Keep soil moist, but not too wet. 
Plants need sunlight to grow, but it's actually light from the blue range of the spectrum that makes plants grow the best. For this reason a simple fluorescent light bulb offers plenty of quality growing light for your starts.  Light from the green part of the spectrum is completely reflected by the plants (why they look green to us) and so is unhelpful to the photosynthetic process. As I just learned from my Certified Horticulturist manual, red light when combined with blue light is best for encouraging flowering, and so the grow bulbs you can purchase are a combination of and blue light but not necessary for starting seedlings. Some crops such as radish, peas, spinach and Swiss chard will do best by direct sowing once temperatures allow, or within the cover of  a cold-frame.
Don't let your seedlings stay in their plug trays or cell packs too long-  they will become weak and leggy.  Before moving your seedlings outside, you need to go through the process of "hardening off."  At least two weeks before planting your indoor starts, begin cutting back on watering and reducing the temperature for your cool season crops by taking seedlings to a shady spot outside on days with little wind and temperatures above 45 degrees.  The shade is important to keep them from scorching in the direct sunlight. This process helps build up carbohydrates and the protective cell walls of the leaf and stem tissue.  It's these thickened cell walls that will help protect your plants from sun scaled, wind damage, and colder temperatures.  Plant according to the seed packet instructions and fertilize with a mild liquid fertilizer.  I like to use fish emulsion.   Happy Growing!


  1. Do you know where I might be able to find heirloom seedlings? Either online or in person? I'd love to incorporate some heirloom varieties into our vegetable garden this year, but feel a little overwhelmed with starting seeds--maybe we'll try it for next year!


    1. Sure. My two favorite sources around town for great quality, organic/ heirloom seedlings are Tricycle Gardens and A Thyme to Plant. Both are great. A Thyme to plant is an all organic herb farm with raw honey, gardening classes etc. Tricycle Gardens is a non-profit in the the city of Richmond with classes and a farm stand in Church Hill. Both usually sell their herb and vegetable seedlings at Lewis Ginter Botanical Gardens Spring Plant Sale.

  2. Southern Exposure Seed Company is a great place to get heirloom seeds. They are a commune outside of Louisa and their seeds are very reliable. If you google them, they have a great website and are super easy to order from!

  3. Oh, and you can also get some good heirloom seedlings at Southern States, Maymont's Herbs Galore, or out front of Elwood Thompsons.

  4. Oh good! Thank you so much. This is really helpful.