Sowing Seeds Indoors

Though most seeds are reliably started indoors, many types are easily started outdoors where they are to grow.

Planning

Good timing in sowing seeds is a key to having transplants of the right size to set out in the right weather. Three important things to know are:
1. The first and last expected frost dates for your area.
2. The kind of weather liked best by the young plants of the types you’re growing.
3. The number of weeks from sowing to setting-out size.

When to Sow

You can ask your local county extension agent for the frost dates and other Seasonal Benchmarks for your area. You can also find this information in publications like the Farmer’s Almanac, and on many Internet Websites by searching for “US Frost Free Dates.” We have provided a place for you to write these down in the chart at right. Some seeds need warm temperatures (about 70° F) or even warmer to germinate. Others need cool temperatures (about 55° F) or freezing to germinate well. Young plants may prefer a different temperature to grow on than the seed did to germinate. Remember that the germination temperatures we talk about refer to soil temperature. Indoors, soil temperatures will approximate the average of day and night temperature for the location. Outdoors, soil temperatures will be slightly below this average in spring and slightly above it in fall.

To find out when you ought to sow, first pick out the right date for setting out in your area; then count back the number of weeks to grow garden-size transplants. Sort your seed packets into groups by their germination temperature requirements, so you will know which ones can be sown together. Before you sow, pick some good locations around your house to set seed trays and to continue growing the seedlings after germination. To find out how many seed trays to prepare, decide first how many plants of each kind you need, and sow twice that many seeds. For each 50 square inches of tray surface area, you may broadcast sow:

• Up to 50 large seeds            • Up to 100 small seeds            • Up to 150 tiny seeds

   One or two varieties may be sown in each seed tray; just make sure to label them. You should sow rather thinly in the tray, allowing enough space so seedlings won’t grow together and get overcrowded before they’re ready to transplant (and to make transplanting easier). If you are starting seeds in individual cups, plugs, or cells, plant 2 seeds per cell.

It may be helpful to use a planning paper like the example given below: (Example: Lexington, VA)