Seed Starting Basics

Seed Starting Basics

Late winter into early spring is the perfect time to start seeds indoors. Most annuals, biennials, and many herbaceous perennials can be grown from seed. Sowing from seed is less expensive than buying established plants and requires little equipment to get started. Growing plants indoors allows the gardener a headstart on the season.

Here at Rosedale Nurseries, we offer a large selection of seeds from Harts, Botanical Interests, Hudson Valley Seeds , Seeds of Change and Renee's Garden. In addition, we carry everything you'll need to get your seeds off to a good start including trays, containers, starter soil and grow lights.



Start with good quality seeds from a reliable supplier. Choose varieties that are adapted to your area. Many new vegetable and flower varieties are hybrids and often have more vigor and uniformity and offer specific disease resistance. If you have leftover seeds from previous years you can use them, but note you may have to use more to make up for poor germination.

Starting Media

A good seed starting medium should be fine, uniform, well aerated and loosely packed. It also needs to be free of insects, disease organisms and weed seeds. Avoid garden soil or potting mixes as they can be contaminated. There are many quality commercial seed starting mixes or you might consider making your own using 3 parts coco coir, 1 part fine vermiculite and  1 part worm castings.


Seedlings require a steady supply of water. It is best to water from the bottom allowing the soil to soak it up. Do not let the soil become water-logged as this will reduce the oxygen available to the plant. Keep the soil moist, but not soaked.


Some seeds need light to germinate and should be surface sown and lightly pressed on top of the soil. Other seeds require darkness and need to be covered. The seed packets should provide you details. Once your seeds have sprouted, they will need supplemental lighting to develop into strong seedlings. Florescent or LED lights suspended 3" above the seedlings, for 16 hours a day will provide the necessary light. As weather permits, move the seedlings outdoors for increasing amounts of time, gradually exposing them to the sunlight.


Most seed germinate between 65-75 degrees F. The ambient temperature in your home should be adequate for many seeds, some may require a warmer medium to germinate. A heating mat placed beneath your seedlings can elevate the temperature of the growing medium and encourage germination. Check the seed packet for temperature requirements.

Hardening Off

Plants grown indoors from seed need to acclimate to the outdoors before being planted in the garden. A week or two before transplanting into your garden, move the plants outside to a shady location for an hour or so, gradually increasing the exposure. Avoid putting out on windy days or when the temperature is below 45 degrees F.


Probably the most difficult aspect of seed starting is when to start. Starting too early can result in poor plant quality that fail to thrive when transplanted into the garden. Use the seed packet instructions as a guide to determine when to start your seeds. Below are links to sowing guides courtesy of Botanical Interests:

Vegetable & Herb Sowing Guide
Ornamental Sowing Guide
What to Sow Indoors 8-10 Weeks
What to Sow Indoors 10-12 Weeks

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