If you like to start plants from seed and don’t want to bear the year-round time and money expense of a greenhouse, consider making hot beds and/or cold frames. These tools can extend the growing season of many crops, such as the ever-delightful home-grown tomato, along with many other plants.

Cold frames protect tender young plants from frost and can usually be set up as early as February, even earlier if you wish to grow cool-season crops such as broccoli, cauliflower, or cabbage. When these plants are ready to go in the garden in March, the cold frame can be used again to start warm-season plants such as tomatoes, peppers, eggplant, squash, melons, cucumbers and annual flowers.

A cold frame is a small, usually rectangular, structure commonly made from wood on four sides with an old window or clear plastic cover for a roof. The sun warms the cold frame during the day and it retains some of this heat overnight like a miniature greenhouse. The frame should be placed in a sunny spot, preferably on the south side of a building for wind protection. Typically the frame slants down from the back to the front to allow for maximum sunshine and minimum shade on the growing area. The covering, plastic or glass, should be easily removable or installed on a hinge so that it can be raised on the warmer, sunnier days of late spring. You don’t want to cook your veggies before their time!

A 4’ x 2’ frame will hold four flats of seedlings and should be made tall enough to allow the plants room to grow. Typically 6-10" on the front and 18-24" on the rear, the height really depends on the frame’s depth from front to back. The idea is to consider the angle of sunshine (along with shadow cast) to maximize the sunlight reaching the flats inside.

Sometimes gardeners use cold frames out in the garden, placing the cold frame over a garden area and sowing the seed directly in the soil. Plants are then thinned and transplanted when they’ve grown and the season is warmer.

If made tall enough cold frames can be used again in the fall, placed over tender crops in the garden to protect them from frost and extending harvest a month or more. Covering a cold frame with old blankets or straw on particularly harsh nights can keep the plants producing even through December.

Hot beds are made the same way as cold frames and were traditionally heated with animal manure which releases heat to the growing seedlings. Bottom heat for seedlings makes them germinate and grow much faster, beneficial if you like to grow a lot of annual flowers. Nowadays heat for the hot bed can be supplied with a special heating cable placed on the ground inside the frame and covered with soil or mulch. The cable will supply constant 70 degree heat to the roots of the happy plants.

Cold frames and hot beds both need daily attention, small packs of seedlings readily dry out when the sun heats the frame, and the cover must be lifted or removed when the temperature inside gets above 75 degrees. Plants may also need to be rearranged to gain more sunshine. If expense is no concern, automatic vent openers can be purchased which open and close depending on the internal temperature, and an automatic watering system can be installed to keep the soil evenly moist.

Gardening with plants you start from seed is a very rewarding experience and it doesn’t have to be expensive or too time consuming.