Plants grow from seeds - DIY planting guide and tips

Generally speaking, large seeds should be planted twice-their-size deep.

Very small, dust-like seeds need light to germinate. Therefore, they shouldn't be covered with soil. Instead, press them into a moist growing medium. Examples: basil, thyme.

About 2% of all seeds require scarification to speed up the germination. Scarification in some instances works better than soaking the seeds prior to sowing - and it's done by rubbing the seeds against the sand paper. That way the water can penetrate the seed coat faster.

There is another 4% of seeds that - in order to grow - require stratification. That simply means that for at least three weeks these seeds should stay refrigerated. In nature, cold winter takes care of that.

Just as an interesting fact I'd like to mention that in Florida (and some other parts of the world) there are some native species of plants whose seeds only germinate after being through the wild fire. That's why we can see controlled fires around the woods in our area quite often.

Photo "Planting spring corn" - courtesy of unereveur

Photo "Nasturtium seedling" - courtesy of Daria Perse

For spring planting outdoors it's best to plant your perennial seeds in the soilless mix - 8 to 12 weeks before the last frost is expected in your area. Perennial plant seeds tend to germinate in about 2 to 6 weeks. Examples: oregano, thyme, lavender, catnip, sage, rosemary, delphinium, coleus.

Annual seeds will germinate much faster - in 1 to 2 weeks - so start them indoors about 6 to 8 weeks prior to the last frost date. Examples: basil, tomatoes, peppers, leeks, snapdragons, summer savory, cucumbers, melons, eggplants.

Why soilless mix?

Usually a mix of peat moss and perlite - soilless mix is lightweight and free of viruses or bacteria that might kill the tender seedlings.

Before planting the seeds, wet the soilless mixture - but don't make it soggy.

If you're starting your seeds in a tray with dome, remove the dome permanently as soon as the germination has begun. Some bottom heat (like from the hair dryer) might greatly speed the germination.

Another thing you can do to grow healthy seedlings is to put them 3" underneath the fluorescent lights - for 12 hours a day. That will force them to start the photosynthesis - instead of growing leggy.

Photo "Planting seeds" - courtesy of mzdinolatino

Once your new plants develop the second set of leaves - so called true leaves, it's time to start fertilizing them lightly:

Photo "Planting seeds of love" - courtesy of Liphart-Designs

The following seeds should be planted to the permanent place in a moist (not soggy) soil - when the ground is still cool - but after the last frost:

broccoli, leeks, peas, onions, shallots, spinach, radishes, beets, carrots, lettuces, chard, kale, bok choy, parsley, chives, dill, cilantro.

As soon as the ground gets warm enough to sit down, it's a good time to add:

squash, pumpkins,beans, turnips, sunflowers, zinnias, cosmos, alyssum, sweet peas, poppies.

Photo "Zinnia seeds" - courtesy of Lonnieatk

Store all the unused plant seeds in a cool and dark place. Many of them are viable for up to 3 years - and you can always use them later.