Start vegetables indoors under lights
Here in the Upper South, it is time to start tender vegetables inside under lights, so they will be ready to set in the garden sometime in the last half of April. Time your own seed-starting to between six and eight weeks before your last frost. Tomatoes, peppers and eggplants need this head start so we can enjoy the harvest that much sooner. Other plants like cucumbers, melons, beans, peas and squash grow so quickly that I just wait and plant them directly in the garden as seeds. Started too early indoors and these plants are often stressed and do not produce. Many new gardeners have poor results in their first attempts and often give up. Chances are, they are trying the wrong varieties of seeds or one of the other essentials is lacking. Once you learn the basics of indoor seed starting and what seeds do best, it isn't really all that hard and isn't that expensive to put together a set-up. Timing is important, as is proper treatment of the seeds and planting medium. Light, moisture and warmth in the proper quantities are all you need.
Tools needed to start vegetables indoors
I always start my seeds either the last week of February or the first week of March, depending on what else requires my time and attention. My set up is simple and inexpensive. I have a snap-together shelving unit from a big box store (about $40) and cheap shop-light fixtures that I hang from chains above each shelf. (about $10 each) Each shelf gets two, two bulb fixtures for a total of four fluorescent bulbs per shelf. Fancy grow-lights aren't necessary since the seedlings will move outdoors before they need any additional spectrum of light. I have a power strip that everything plugs into and that makes it easy to turn on and off as well. Depending on how many seeds I intend to start, I can have as many as three shelves full of plants. This year, I'm just going with one shelf, with two trays of seedlings. When they grow big enough to transplant, I'll light up another shelf to take into consideration the larger containers. Many people like peat pots and expandable cubes for seed starting, however I prefer not to use them myself. They are hard to maintain proper moisture levels and are not a renewable resource. I like the reusable plastic trays with the individual cells that I fill with seed-starting mix. I set my system up in my dining room in front of my large south-west facing bay window, to take full advantage of the extra light the sun provides as well.
Prepare the seed starting mix properly
Once I have my shelves and lights in place, it is time to plant the seeds. I only use sterile seed-starting mix. Regular potting soil isn't sterile and can introduce mold, fungus or any other pathogens to the fragile seedlings as they germinate. Pour a good amount of the mix into a large bowl or bucket and moisten with warm water. Warm water absorbs better than cold and you get a better feel for how moist the mix is. The mix only needs to be damp enough to feel like a sponge that you've wrung out until it doesn't drip. Damp enough to feel damp, but not wet. First time seed starters mistakenly think they need more moisture than they do and over-water from the start. Don't make that mistake. If you can squeeze the mix in your hand and water drips out, add more mix. Wet soil doesn't hold oxygen and you need oxygen for good germination. It should still be somewhat fluffy and not clump together. Fill the cells of your seed starting trays and tap the mix down with your fingers to firm it up. You don't need to pack it tightly, however it does need tamping down a bit.
Plant tomato and pepper seeds indoors
Now, you're finally ready for your seeds. I plant only one variety at a time and carefully seal the packages back with tape, so that the seeds do not get mixed up. Pay attention to the counter and your hands so you do not leave seeds laying around or stuck to anything. There's no way of knowing what the mystery seeds are after the fact. You may know they are tomato seeds, however there's no way of knowing which one, if you are planting more than one variety. That may not matter if you aren't planning to save seeds, however it is extremely important if you are. I've also cut plastic strips from plastic milk or kitty litter containers that I write the variety name on with a marker. With a small stick (I use mixed drink stirrers) I poke a hole in the mix about 1/4 to 1/2 inch deep for tomatoes, peppers and eggplants. Carefully tap and press the mix to cover your seed and place the marker at the edge of the cell. Your seeds need the contact with the moist mix to germinate, however they do not need excessive packing. Place the clear cover on each tray, or simply lay a piece of clear plastic wrap over it. All this does is retains the humidity and you should see no more than a bit of mist on it after a day or so. If you have water large droplets, your mix is too wet and you should remove the cover to help it dry some more. Place the trays on the shelf and lower the lights to about two or three inches from the lid and turn the lights on. The warmth from the lights warms the soil and helps the seeds to germinate. I leave the lights on 24/7 until the plants start to emerge.
Watch for germinating seeds
Tomatoes should start to germinate in less than a week. Peppers and eggplants might take twice as long, so I put them in their own tray to keep the cover on them longer. If you only have one tray, just lay plastic wrap over the late starters. As soon as the seedlings start to emerge, remove the clear cover or plastic wrap. You do not have to wait until they all germinate. As soon as you see a few, the cover needs to come off. Its job is done. That's another mistake. Many of the commercial labels for these trays show blooming plants with the plastic cover still over them and that is so wrong. All the covers should do is keep the humidity and warmth enclosed until germination starts. The little plants need fresh air and less humidity.
Proper lighting and moisture is important
Once the seeds start to germinate and the cover comes off, you need to move the lights to just a couple of inches above the plants. This is another common mistake. People who are not familiar with starting seeds indoors almost invariably keep the lights too far from the plants. They strain toward the light and grow long and leggy. With the lights close to the leaves, the plants grow stocky and strong. That's why I keep the lights on chains where I can raise them as the plants grow. If you are using LED lights, raise them a bit more as they tend to be more intense than the fluorescent ones. This is also the time when I only leave the lights on for 12 hours, so the seedlings experience night time and cooler temperatures. The first little leaves that appear are not true leaves. They are called cotyledons and were present inside the seed before it germinated. They help nourish the infant plant until the first true leaves emerge, which usually do for tomatoes and peppers about a week after they germinate. Keep the lights close to the seedlings and monitor the moisture in the soil. Only water when the top layer of the soil appears dry and then do so by pouring room temperature water in the base of the trays. Watering from the bottom encourages the roots to grow down to search for it and keeps the top layer drier to prevent mold and fungus. If your top soil is wet, fungus gnats can appear and while they do no harm, they are definitely aggravating. I pour about a half inch or so of water in the trays and monitor the seedlings to see when the potting mix starts to darken on top. That means that the soil has enough moisture. After that, I pour the excess water out of the trays. Don't let the water sit in the trays for long periods of time. That encourages the soil to take up more than it needs and then it becomes waterlogged. Also, there is no need to feed the little plants with fertilizer. This is another misconception. That stimulates top growth and they need to develop a healthy root system first.
Transplant to larger containers
When the seedlings have one set of true leaves and a second set starting to emerge, you can transplant to larger containers so that they can grow to the size they need to be before they are set in the garden. I still use a sterile potting mix and dampen it just like I do for the seeds. I use 8 ounce plastic cups like you'd buy for a party. The only requirement I have is that the bottoms of the cups sit flat on the surface instead of the raised ridge that many of them have. The ridge is meant to keep moisture rings from forming on furniture and we need the flat bottoms so that the plants can draw moisture from the trays. I take an ice pick and poke several holes in each bottom and they are ready to plant. Drop a little potting mix in the bottom of the cup and then lift the baby plant from the seedling cells by running a table knife down the side and popping them out. Put them in their larger homes and add the potting mix and firm it us so there's no big air pockets. Take a marker and write the variety right on the cups. You'll need extra trays to accommodate the bigger containers now. Keep them indoors for another week to ten days to let them start to build more roots.
Harden seedlings off with time outdoors
Once the seedlings have settled in well, you can start hardening them off with short visits outdoors. I use my east-facing front porch. It is covered and the sun is only on the the seedlings for three or four hours. I leave them outdoors during the day even though the sun isn't actually on them because the light is brighter and the breeze will toughen them up some. If the temperature goes below 50 degrees Fahrenheit, I bring them in, or do not put them outdoors at all. They aren't going to grow much in those conditions anyway. By this time, you should be getting close to the time you set your seedlings in the garden and I leave them outdoors all night the last week or so. Your seedlings should be tough and ready to start their lives as productive garden plants. They will get their best start in well-prepared ground with a bit of an all-purpose fertilizer mixed in. If you can, transplant on a cloudy day. This lets the little plants acclimate to their garden home better than doing so in the hot sun.
Starting seeds indoors is educational and rewarding
The main things to take away from this is that too much water causes problems and light is very important. I've raised thousands of seedlings inside under lights over the years and this system works best for me. It isn't the only way to do it, some prefer peat pots and others prefer to plant their seeds in the same container that they ultimately grow to setting-out stage. Keep things clean, the soil sterile and monitor moisture and light carefully until you understand what it takes to start seedlings and you'll do fine. This is also a good home school project for the kids. Starting your own seeds indoors before the gardening season gets underway gives you the chance to try plants that your local businesses may not offer and while you do not actually save much money, you know exactly what has gone into the seedlings you grow.