While it would be impossible to list all of the types of seed you might want to start indoors, this lists the most common varieties. To determine when a type of seed should be started, you find out how long it takes to go from seed to transplant. Sometimes this information is on a packet, other times you have to look it up in a reference book. If it is a tender plant, you count back from late May. If it is a cold tolerant plant, you can count back from early May.

SEEDING TIPS:
Seedlings will do best with 14-16 hours of light each day.

Some seeds need dark to germinate. Others require light. Check the package.

Seed starting material should be light, holding both moisture and air.

Most seeds germinate best at 72º  A few varieties germinate best at cooler temperatures.

Check the package.

Some seeds need a cold treatment before they will germinate. Packaged seeds should have been pre-treated.

Water seeds and seedlings with lukewarm water.

Minimize problems with damp-off by improving air circulation.

Regular fluorescent light works fine for seedlings. Grow lights are only needed for blooming plants.

You don't need sterilized soil since most of the micro-organisms in potting soil are beneficial.

The first leaves to emerge from a seed are called cotyledons. The next set are true leaves.
As soon as seedlings have formed true leaves, begin fertilizing with a water soluble solution.

To avoid disturbing fine seed, moisten your potting soil before sowing.

Seeds that are extremely fine are often available pelleted for easier seeding.

Keep seedlings as close to the source of light as possible. You can put cool fluorescents within inches of your plants.

Cole is a collective term for cabbage, Brussels sprouts, broccoli, cauliflower, collards etc.

Use a humidity dome during seed germination, but air it out daily. Remove humidity domes as soon as the seed begins to germinate.

Soak parsley and tomato seeds overnight in warm water to speed up germination.

A few seeds are very difficult to germinate indoors. An example is lavender … it requires pre-chilling, then 30 days at 45º.

Seed sizes vary greatly. Begonias have over 2 million seeds to the ounce. Nasturtiums have only 175.

Morning glory seed germinates best when the seed coat is nicked before sowing.

Sow large seeds such as sweet peas, morning glories , nasturtiums and melons in individual pots or Jiffy 7s.

Moving your light source an inch closer can almost double the amount of light available to your seedlings.

How sweet or hot your onions will be is determined both by the variety and the amount of sulfur in the soil.

Cilantro and coriander are the same plant. Harvest the leaves and it is cilantro. Harvest the seed and it is coriander.

Cilantro, dill, lettuce, carrots and radishes can be sowed every three weeks to keep a supply of tender, young plants to harvest.

Calendar for zone 4, Minneapolis Minnesota.

By the end of January, you should have seeded
Lisianthus, geraniums, begonias and gerbera daisies.

In mid to late February, start seed for snapdragons, geranium,
dusty miller, verbena, thyme and periwinkle (vinca).

Early to Mid-March

Seeds of cold-tolerant varieties such as peas can be planted outdoors by late April.

Early to Mid-May

You may still want to start a few pots of cucumbers, squash, watermelons, zucchini and morning glory. It is also a good time to start successive sowings of lettuce, carrots and radishes.