Seedstarting the basics
Now that you’ve got all the necessary ingredients ie your seedstarting pots, the growth medium, the seeds, you’re ready to get started proper. Fill your seedstarting containters so there’s about 1/2 inch off the top. Use some warm water (treat them nice, how would you like it if you got dunked in some freezing water on your first day out?) and moisten the growing medium. If you haven’t already done so, read the seed packet BEFORE you plonk the seeds in, some seeds (those with hard seed coats) need what’s called ‘pre-soaking’ beforehand, others need chilling.
Depending on the containers you’ve picked, you can either scatter the seeds over the surface of the growth medium or sow them individually into growing cells. Cover with a fine layer of the growth medium (usually to a depth of about 3 times their size). DO NOT sow too thickly. This is when I then use a fine mist of water (to gently moisten the growth medium surface for extra moisture) – I find that using a watering can in this instance can wash the soil from the seeds and move them so I avoid using the watering can. Label the container with the seeds you’ve sown for easy reference later – I usually also add the date sown.
Seedstarting – working out the essentials
Optimum germination temperatures are usually listed on seed packets – note that these temperatures are soil temperatures, not air temperatures. The soil often takes a lot longer to warm up (that’s why earth is such a good insulator). Most seeds prefer soil temperatures to be about 75-80 degrees Fahrenheit (not all do, so read the label). Some gardeners put the containers on a warm window sill, on top of the refrigerator or in the sun-room or in their greenhouse to speed up germination, other more sophisticated methods would include the use of heated germination trays. If you’ve placed your containers in a room that hasn’t got sunlight, just remember to move them to a window or provide some artificial form of light after they sprout. Once they’ve sprouted, the seedlings don’t need the temperatures to be as warm, somewhere around 70 degrees Fahrenheit is good, you want to grow them slowly so that they don’t bolt and end up weak and leggy.
Unless you’re germinating something like snapdragons, most seeds don’t need light to germinate. Having said that, once they emerge from the soil as sprouts, they do need the light. So check your seeds daily and once you see them emerging, it’s time to move them to that sunny spot near the window or under growth lights. Seedlings need about 12 hours of direct light to grow well so make sure they are getting that in your choice of windows (a south facing one is best). Artificial lights work well to provide this if you don’t have a south facing window handy. Note that if you are using artificial lights, you need to use either a combination of cool and warm fluorescents or the full spectrum fluorescent lights – NOT the light bulb (incandescent) lights – these don’t provide the full spectrum of light that the sprouts need to grow properly and are oftentimes too hot.
Most gardeners just use plastic bags to cover their seed trays till the seedlings appear to keep the moisture in. If you have plastic seed trays with covers that come with them, these need to be removed once the seedlings appear. Use warm water to baby your seedlings. I use warmed up rain water – I use a plastic recycled water bottle, fill it up with rain water and put it in the sun. To ensure that you’re just not watering the soil surface and neglecting the root system, you might want to fill a tray with water and place your containers on the water to allow the water to soak from the bottom up. Just make sure you remove them once you feel the soil surface is moist.
Winter air (and central heating air indoors) often doesn’t have the required humidity levels for optimum seeling growth. You are aiming for somewhere between 50-70 percent, any higher and you’ll have fungal problems. You can provide a more humid localised environment for your seedlings by sitting them on capillary matting or filling a tray with water and sitting the seed trays on top of small stones/gravel.
Feeding your seedlings
Once your seedlings get their first set of true leaves (this refers to the second pair that appears – the first pair aren’t ‘true’ leaves), it’s time to feed them. Mild half strength fertilizer is best – once a week with some weak half strength fertilizer (I use the dregs from my worm farm) is best. Do this for about a month and then you can start upping the dose to full strength on a weekly basis.
Potting up / transplanting
You’ll know when it’s time for your babies to go out to the real world when they start looking a bit crowded in their trays. Transplant stress kills a lot of seedlings so take extra care. Try to handle seedlings by holding onto their leaves or roots, holding them by their stems often bruises the stems which is a surefire way of killing them before their time.
When you’re ready to separate them, do not water beforehand, I use a small teaspoon to scoop the seedlings out and then pry them apart gently with an ice-cream stick. Most seedlings you plant at the same depth or just a tiny bit deeper – tomato plants are different, you should remove all but the top few leaves and bury the rest of the stem and roots into the soil to get a deeper and stronger root system. Once you’ve repotted them, water well, fertilize and then return them to the sunny windowsill or grow lights
As you notice the weather warming up (usually best to note when the last frost is for your area), you can start ‘hardening off’ your seedlings. This is just the gardening term for toughening them up so they are ready to handle the rougher conditions outdoors. Start by planning to harden them off about a week before you’re going to send them out to the real world. You begin by reducing the amount of water and fertilizer you provide for them. I usually plonk them outside in the shade of one of my trees for a couple of hours daily – gradually increasing the time they are outside till they are outdoors all day (but in the shade). Then on the day of reckoning (I usually try to pick an overcast day and one which isn’t too windy) I plant them out, water them well and drizzle them with some sea kelp fertilizer (which stimulates strong root growth) and wish them well.