Carol O'Meara - Colorado State University Extension

Carol O’Meara – Colorado State University Extension

If you have a dog that greets you with enthusiasm when you come home, dancing about your feet and letting you know you’re the best thing that’s happened to them all day, you’ll understand what my spouse is going through at our house right now. Instead of the dog, however, it’s me he has to navigate around, as I rush him in my eagerness to see what’s come in the mail.

He knows I’m happy to see him too, but this time of year is when my seeds arrive, and he has a bit of fun teasing me with the packages before I knock him down and grab the packages with a hiss of “my precioussss.”  At least he knows I’ll be happily occupied for the next hour, cooing over each and every paper packet.

February is the time to start some seeds, so clear off shelves, wash out trays, and get your lights set up. To get started, choose an area that will hold the seed trays for six weeks or longer in a space that remains 68 to 70-degrees, out of drafts and traffic.   

Different methods are available, such as open flats, plastic trays with small, 1-inch square cells, peat pots, or peat moss in mesh netting (Jiffy Pellets). Almost anything can be used, even egg cartons. Those made of Styrofoam need drainage holes poked into the bottom of each cell; the pressed paper ones don’t but they break down quickly.

Purchase trays that suit your style, or clean and sterilize those you already have by dipping them in a solution of 10-percent bleach in water. Be sure to rinse the trays two or three times before using, since bleach is lethal to plants.

When it comes to the soil, don’t scrimp: use clean, high quality soilless mixes; you get what you pay for with seed starting soil.  Consistency and uniformity means good distribution of moisture and air for roots. The ideal media for starting seeds is a lightweight, soilless mix of peat, vermiculite, or perlite and compost. Using a sterile mix avoids disease problems like damping off, caused by a fungus that attacks tender stems at the soil line.

The important thing is good drainage, so set the tray on another tray that’s filled with pebbles. Line the lower tray with Saran Wrap to keep it from leaking onto the floor. A bigger danger to seedlings is drying out; monitor your seed trays closely.

Use plant labels to keep track of varieties and avoid confusion. As plants grow and are moved into larger pots, transfer labels, too,
so you’ll know which seedling is which.

To help germination, use a humidity tent, a plastic covering that holds moisture in. Bread bags are ideal tenting because they breathe, while shrink wrap is a no-no because it doesn’t; milk jugs with the bottom cut off make good covers.

As seedlings sprout, crack open the container to let air circulate inside and immediately place the trays under lights so plants don’t stretch and become leggy.  Seedlings should be stocky; if yours start reaching, lower the light to be closer to the plants.

Seedlings need plenty of sunshine, but if you don’t have a sunny southern window to put them in, you’ll need lights. Start seedlings under a fluorescent shop light with one cool white and one warm white bulb. Lights should hang directly over seed trays on cords or chains for easy raising or lowering. Hold lights 3 to 4 inches above the plants at all times, and give them 14 to 16 hours of light daily.

By Carol O’Meara, Colorado State University Extension
Colorado State University Extension, together with Boulder County Parks and Open Space, provides unbiased, research-based information about consumer and family issues, horticulture, natural resources, agriculture and 4-H youth development. For more information contact Extension at the Boulder County Fairgrounds, 9595 Nelson Rd., Box B, Longmont, 303.678.6238, e-mail [email protected] or visit