Seed starting 101

Seeds are amazing. Inside that tiny structure is everything necessary to produce a new plant.

A seed is composed of an embryo (baby plant), endosperm (food source) and seed coat (protective covering). Seeds will germinate (sprout) when the proper environment is provided.

Timing is key

Knowing when to start seeds indoors is the most critical step. First, determine the number of weeks it will take to grow the plant to transplant size. This number varies and is usually listed on the seed packet.

Now determine when the average date of the last spring frost is for Rochester. Depending on which resource is used, the average date of the last spring frost in Rochester is between May 1 and May 10. I use May 10 as the date.


Now count backwards on a calendar starting from May 10. As a general rule, most seeds should be started six to eight weeks before the average date of the last spring frost. March 29 is six weeks from May 10.


Any container with holes in the bottom to provide good drainage can be used. Biodegradable peat pots and seed-starting flats can be purchased, or you can use re-purpose materials like egg cartons or milk jugs.

I like to use the clear plastic containers that produce comes in. These containers have drainage holes and a clear cover to increase humidity and warmth.

Seeds are fussier when it comes to germination media (soil). The germination mix should be sterile and weed-free, so do not use soil from the garden. The media also needs to hold water but at the same time drain well.

High-quality seed-starting mixes are available at local garden centers. Do not skimp on the germination media!

Many seedlings look alike, so don’t forget the labels. Popsicle sticks or plastic knives make great labels.

Remember to keep the seed packets for future reference.


The proper environment

Seeds vary in the amount of light required for germination. Some seeds require light and should not be covered with the growing media. Others do best with some light and should be covered lightly with the germination media.

Still others germinate best in darkness and should be covered with about a quarter of an inch of germination media. Check the recommendations on the seed package.

Soil temperature is more important than air temperature. During seed germination, the recommended soil temperature for most seeds is 75 degrees. A warm, humid environment encourages germination, so cover containers with clear plastic.

Water softens the seed coat and initiates the germination process. I water by capillary action (by putting my container in a saucer of water). Remember to keep the seedlings evenly moist. Do not use softened water.

After germination, light is essential for all seedlings. Seedlings require 12 to 16 hours of light per day. A combination of natural sunlight supplemented with artificial light is the best.

If seeds are started too early, they will have to be kept inside too long and the seedlings will be weak at transplant time. Don’t become too anxious with this warm weather we are having. Mother Nature may still turn cold.

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