Common Seed Starting Problems
Your seeds are planted indoors...now what? Besides "wait," you'll want to keep a check on them regularly, even daily. (OK, I am obsessive and check them twice a day.) Seedlings can be delicate creatures and susceptible to problems while they grow. Luckily most issues can be narrowed down to one (or more) of three things:
Pay attention to those three things and you'll be well on your way to healthy seedlings. But, it's still important to keep an eye out for (and try to prevent) some of these common seed starting issues.
Seeds Don't Germinate
This could happen for a number of reasons:
Old seeds: You can typically store seeds for a while and plant some each season, but their success rate may be reduced the older they get. Some seeds never do well beyond the year they were produced for planting, like parsnips. Parsnips should always be planted in the year they were purchased/intended for. They don't do well after that. To check if your seeds are still good, try the water test or germination test outlined by Horticultural Magazine.
Incorrect temperature: Seed packets usually tell you the temperature at which the seeds will germinate (typically 70-80 degrees F). I've never actually taken the temperature of the air or soil around my seedlings, but I always use a seedling heat mat to keep them warm and it works well. Especially if you have them in a cold basement or similarly cold area, you should look into putting a seedling heat mat beneath the tray.
Seeds Planted Too Deep/Inadequate Light: Even though photosynthesis may not kick in until the true leaves appear, some seeds do need light to germinate. Refer to the recommendations on your seed packet for planting depth. Seedlings need 15-18 hours of light per day, so if you're just putting them by a window, that is likely not going to be enough light (nor a high enough temperature). Use grow lights to provide adequate light. Also make sure they're not too high up from the seed trays. I actually just lowered my lights closer to my seed plantings because I think they were too far away.
Soil too wet/dry: I use a system that waters the seedlings from underneath and I make sure that I keep on top of the water levels. Don't oversaturate the soil or neglect them and let them dry out.
Spindly Long Seedlings
This happened to me the first time I tried to start seeds indoors. I just had no idea what I was doing and thought my sunroom would be a great "greenhouse." It wasn't. When seeds get long and spindly, they're trying to get the light they crave. They're "reaching" for the light. Make sure you use grow lights and that they're close enough to the seedlings that they don't have to "stretch" to get it. Even if you see the seedlings leaning too far to one side, they may be trying to catch light that's too far away to one side.
Damping Off (Fungus)
Damping Off is a fungal infection that can ruin seedlings. When this occurs, the seedling can just suddenly keel over and die. This can be caused by soil that is too moist, too many seedlings crowded in one space or unsanitary planting conditions. Once damping off has occurred, there's no "cure." Remove the affected plants to prevent the spread of spores. To prevent this condition, it's beneficial to use a watering system that brings water up from the bottom of the seedlings and don't overcrowd the seedlings - it can cause humid conditions.
Keep an eye on things every day if you can, particularly in the early stages of growth. I hope that doesn't turn you away from the appeal of starting from seed indoors. This isn't a huge time commitment, but just a matter of keeping everything in check and addressing issues as soon as they hit. Pay attention to temperature, light and moisture and you'll see some great seedling growth.