If you are new to starting seeds indoors, you will need to get a few things:
- A cheap 4′ workshop light and a set of 4′ cool and warm fluorescent lights (a must for those with cooler climates and shorter growing seasons). Don’t get the plant-specific lights as the regular ones are just as good. Alternate the cool and warm bulbs if you are putting more than one set of workshop lights side-by-side.
- A timer set to turn on 14 hours and off for 10 hours a day (optional if you’re good at remembering).
- A heating mat (optional, helps germinate harder/longer-to-germinate seeds like parsley and hot peppers)
- Soilless seed starting mix
- 72-cell seedling insert trays (breaks down into eight 9-cell packs)
- Plastic propagation trays
- Clear plastic domes
- Used 1” plastic blinds
- Oscillating fan (optional)
- 4” pots
- Potting soil
- A black paint pen
Once your seeds sprout, remove the clear plastic dome and place them under the lights. The dome also helps the seedlings remove their seed coat as they push through the soil. If some of your seedlings still have their seed coats on, mist and cover with a narrow shot glass – within a day you should be able to remove the seed coat easily with your fingers. Suspend the lights so that they are two to three inches above the tallest sprout. Plug the lights into the optional timer. Every second day, run your hands over the tops of the seedlings to help them strengthen the stems – this will help prevent leggy seedlings. Or you can place an oscillating fan on them about 3′ away on low for an hour every other day.
Water seedlings from the bottom, not the top to help prevent damping off. I pour enough water in the tray for the seedlings to be standing in 1/3 of water. Remove any excess water from the plastic tray after 10 minutes. I usually water once a week.
Once your seedlings have outgrown their cell inserts, pot them up to 4″ pots with dampened potting soil. Use more cut up blinds to label with a Sharpie. You’ll want to start acclimatizing them to real indoor sunlight at this point. While still indoors, put them in indirect sunlight for a few hours a day. Build that up SLOWLY so that they can withstand full sun. This will take about a week. If you start noticing whitish spots on the leaves, you’ve left them too long in the sun and they now have sun damage.
A couple of weeks before you plant out in your garden, you will need to harden them off to the outdoors. Again, build that up SLOWLY as you don’t want to shock them. Put them outside in a shady, wind-free spot on a cloudy day for an hour or so. Build it up so that they can withstand full sun, rain and overnight temperatures. This takes a while and you’ll have to be patient. Keep an eye out for whitish spots and curling leaf edges as this will indicate sun and wind burn. Keep watering from the bottom. Try not to touch wet tomato leaves as this increases the risk of leaf mold.
Transplant into your garden and use a 6″ piece of blind to label the plant with a paint pen (don’t use a Sharpie for this as the sun will make the marking fade by the end of the season). Don’t fertilize for the first week as your seedlings will be in shock and will need time to settle into their new location.
Remember to succession sow seeds for a continuous supply of produce. Lettuce, radishes, spinach, bush beans, beets and carrots are good for this. Also start a fall harvest of peas, broccoli, cabbage, kale, summer squash, spinach and lettuce.
Also, buy an airtight food storage container to hold all of your seed packets to help keep them dry. Organize them in alphabetical order by Direct Sow, Vegetables, Herbs and Flowers. Keep an inventory if you want to be extra organized.
During winter, get in on seed exchanges or swaps in places like GardenWeb to trade your seeds and try out new stuff.
That’s pretty much all I can think of. Let me know if anyone else has any tips for a new indoor sower.
(taken from a gardening forum post I wrote)