Hi Robert –
To start seeds early when it is still cold outside — and frosts are possible — will require protection from a mini greenhouse or cold frame. Not sure you want to invest in something so elaborate? Many growers use clear plastic milk jugs cut in half, repurposed strawberry containers, or covered plastic bins to keep soil and seeds warm during cold weather. A heat mat can also be used outside to warm the rooting area 10-20ยฐ F over ambient temperatures. This will greatly improve germination success, just make sure it is protected from the elements.
When selecting vegetable seeds to grow outside, look for heirloom varieties that are adapted to your region and buy seeds packaged for the current growing season. We’ve always had success planting cold-weather crops like lettuce, carrots, chard, and spinach early in the growing season. Flower seeds such as clarkia, columbine, California poppies, sweet peas, sunflowers, nasturtiums and others will do better if they are sowed directly in the ground.
Note: For extra protection, you can turn your cold frame into a hot box by adding rotting manure or a layer of leaves or straw seasoned with microbe-rich compost beneath your soil layer. The heat generated by the decaying organic material will help hold plants over winter as well as give soil temperatures a boost in time for spring germination.
Hope it helps!
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