One February I remember my father going out into the garden and planting seeds. We had had a good bit of snow the previous week and there were still reminders of it in the shadier parts of the backyard. However, the sun was out, the temperature had warmed and the snow had melted away in the garden. This February, just like my Dad, I'm planning to be out in the garden planting seeds, weather permitting. When I asked my dad what he was doing that day he replied, an “experiment”, but in actuality he was pre-seeding the garden.
Pre-seeding reminds me a little bit of “winter sowing” but with out the jugs. They both allow for an earlier start to the growing season, the plants are already conditioned to the outside so there is no need for “hardening off” and there is little or no chance of transfer shock which makes for healthier plants. Plants started indoors are grown under “controlled” conditions and even with proper transition to the outside will still go through a period of stress. This stress delays the plants growth, makes it vulnerable to insect and disease, and reduces productivity. In addition, not all vegetable seeds should be started indoors: if it grows under ground then direct sow with the possible exception of onions. Seeds of peas, beans and corn may be started indoors but are tricky to transplant outdoors and will most likely suffer for it.
Many annual seeds weather the winter because of sheer numbers. They produce an overly abundant amount of seeds so some are sure to survive. However, a cold spell is not required for annual seeds to germinate. The “relative cold tolerance” of annual seeds as it applies to seed germination can be broken down into hardy, half-hardy and tender(tropical) annuals. This should not be confused with plant cold hardiness and may not correspond. Hardy annual seeds can handle being frozen and can be planted in late fall or as soon as the ground can be worked in early spring. Half hardy annual seeds do not tolerate being frozen and should be sown after the ground has thawed but it's not necessary for the soil to warm up. Tender (tropical) annual seeds should be planted only after the soil has warmed and all danger of frost has passed.
The ideal time to pre-seed veggies seeds is when the temperature has dropped and there is little chance of freeze-thaw cycles. Germination begins when the soil temperature is within the minimum/maximum range and seeds absorb water and swell. Once germination begins it can not be stopped. Air temperature is critical for sprout survival. A warm spell sufficient to start germination that is then fallowed by a cold snap will kill seedlings. (During the winter soil temperature is warmer then the overlying air temperature). “Optimum soil temperature” is the temperature at which you will get maximum germination in the shortest amount of time. Percent of success on seed packets is based on optimum soil temperature. If conditions are not 100% ideal, sow seeds a bit heavier then suggested. You can always thin them out later.
Select the area you plan to pre-seed in the fall and make sure it's not an area prone to standing water come spring, which will rot your seeds. Prepare the garden area by removing spent plants, weeds and other debris. Add more soil if needed and work in compost. Cover with shredded leaves, straw or other mulch. When it's time to plant pull back on the mulch and sow according to the directions on the seed packet as it pertains to seed depth and spacing. Spread the mulch back over your newly planted areas. Some of the more cold hardy veggies seeds are your root vegetables, lettuce, peas, celery, swiss chard, spinach, “cole crops” like broccoli, brussel sprouts, cabbage, cauliflower, collards, kale, mustard greens and kohlrabi. The area I'm planning to pre-seed is between my rows of already planted garlic. I allowed for extra spacing (twelve inches) and all except peas are good companion plants.