Follow the instructions on the seed packet. Most brands will include information for success. Or go to the website and look for information. Each variety of seed you have selected is likely a different species. A cat and a hamster are both furry pets, but are different species and need very different care. Ditto plant species. Granted, some needs are quite similar and you might get away with treating them all the same – or you might not.
Seed growing instructions usually include timing, usually the number of weeks before the last frost date. If you want to get a head start indoors, you still need to provide the required outdoor conditions. You can’t cheat nature, but you can replicate it. Temperature, light, moisture, wind. And if the instructions say that “starting indoors is not recommended”, you’ll likely fail if you try.
Seed will germinate at the right temperature, but getting the seedlings to thrive and grow into healthy little plants is what’s challenging. Artificial light is not sunlight. It will do for a few weeks, but not for months. Seedlings also need good air circulation. Outdoors, wind provides this. Air circulation helps prevent damaging soil fungi from growing. So, if your indoor air is still, it’s better to keep your soil on the dry side and water from the bottom. This also helps the roots develop, as they have to reach to get water. You want reach, not rot, right?
Wind also exercises the stems and roots, to make them sturdier, as they bend back and forth. Most fans don’t create a straight breeze, but instead a corkscrew effect, and seedlings grown close together can twist and get tangled.
Timing is pretty important. If the instructions say to “start indoors 6 weeks before last frost”, starting in January for a May last frost is risking failure. You might end up with just dead seedlings in March. Or if your unhealthy stringy, yellow seedlings make it to may, they may not survive the stress of transplant. It’s a bit like transplant surgery in humans. The stronger the patient, the better the chance of survival.
Since my garden is less than half an acre, those seed starting flats that box stores like to sell don’t work for me. Especially the ones with the compressed pellets as the medium. Those pellets are usually too compressed, even after they fluff up. Seedlings need loose mix for their young roots to spread. Also, if you’re not growing a tray of the same species, and the different species need different growing conditions, how do you control light, temperature and moisture? And who has the space? If half of them fail to germinate or die off, you have a tray of scraps with pest and disease growing in the graves in between.
I got smaller trays at a dollar store years ago and have reused them over several years. They also don’t fall apart as easily, since they’re smaller and don’t flop about when you’re trying to get plants out of them.
It’s important to plant with moist starting mix. I moisten a batch to use, and keep the rest dry. Dry mix is a mess to water from above and your seed will float all over and end up in one spot. With moist mix, there’s no need to water until germination. Watering from the bottom is the best way, so keep the seedlings healthy.
It’s easy to turn potting mix into seed starting mix by sifting out the larger particles and sterilizing it. I just nuke it in the microwave, in a heat resistant bowl, after running it through a soil strainer. The one in the photo comes with 3 inserts for various coarseness. Also consider using clean, sterilized pots (I use bleach).
Ok, I do use the full trays. Bigger ones even (black in the back), for working with, because potting mix gets everywhere when you’re filling cells. The green and tan are Permanest and have simple and vented clear dome options. I’ve had the same ones for over 15 years and they are in excellent condition. They’re great to use for bottom watering. Photo on the right shows my setup on a table, over a radiator, by a south-facing window. Below is the complicated version, with LED lights and heat mats.
