Seed starting

The main reasons for starting seeds indoors are to get a jumpstart on the growing season and to grow a greater variety of vegetables than would be available at the nursery. Before selecting vegetable varieties, check the seed packets to determine the number of days until harvest to make sure you select varieties that will ripen before the first frost in the fall. Transplants require several weeks to grow, so consult the seed packet to find out how many weeks each variety will need before being transplanted out. Using the average last spring frost, determine the best time to start seedlings indoors by counting back the number of weeks needed to grow seedlings that can withstand the various spring soil temperatures.

Once the seed starting date has arrived, gather all your seed starting supplies:

• Seeds to be started
• Containers to sow the seeds in (2-3” wide)
• Germination mix or peat pellets
• Water (preferably warm)
• Plant tags to keep track of what was planted in each container (I like plastic tags the best)
• Black sharpie marker (other colors fade quickly) to write on the plant tags

When to start seeds

Transplants require several weeks to grow, so it is important to get your seeds started early, but not too early. Starting seeds too early results in large plants that need to be potted up multiple times before being transplanted outdoors. This not only takes up a lot of space, it is a waste of time and money. 

US Hardiness Zones (courtesy of the USDA)

Starting plants from seed requires careful planning and knowledge of ones growing season. To determine your growing season (last and first frost), find your location on the US Climate Chart and refer to the USDA Hardiness Map to identify your hardiness zone. 

The last frost refers to the average date on which a particular area no longer experiences freezing temperatures in the spring.  

The first frost refers to the average date on which a particular area experiences its first freezing temperatures in the fall.

In the spring, I use the date after which there is only a 10% chance of frost to determine when to start seeds. In my region, the average last frost is April 19^th. The chance of frost after this date is approximately 10%. This does not mean that there is no chance of frost, but based on previous years, it is unlikely that there will be a frost after April 19^th.  From this date, I count back the number of weeks needed to grow strong transplants based on the information that is on the seed packets.  

This year, I am paying extra close attention to the recommended dates for starting seeds in relation to my growing season to minimize the number of times I have to pot up before transplanting outdoors.  Will I succeed?  Stay tuned to find out.

“Soil” for seed-starting (and beyond)

Top: Potting Mix
Bottom: Germination Mixes
from different companies

“Soil” has three main functions: 1) provide physical support for the plants, 2) supply roots with nutrients, air, and water, and 3) allow maximum root growth. There are different formulations of this medium that are designed for starting seeds, potting up seedlings, and transplanting plants. Selecting the right mix (at the right time) is essential for raising healthy transplants.  

The best growth medium used for starting seeds is not actually soil. It is usually a blend of sphagnum peat, vermiculite, perlite, and lime, but may also include coir, sand, and other ingredients. This soil-less seed-starting mix (also called “germination mix”) can be purchased from any garden center or online retailer. You can also prepare your own germination mix at home. A simple recipe is 1 part Sphagnum peat moss, 1 part vermiculite, and 1 part perlite.