I gave them too much water: I know that seedlings have to stay damp to germinate. I didn't realize that too much moisture after germinating would cause damping off. This is when the seedling stem rots where it meets the soil surface. I did know that it doesn't take very long for a seedling to dry out if it doesn't have enough moisture. Dry seedlings are dead seedlings. In my effort to prevent dry seedlings, I caused damp seedlings. Neither one is good. Let the soil dry out slightly between waterings.
Not enough light: I thought I had enough natural light. I thought the room lights would be enough added light in the evenings, after all the lights in that room were broad spectrum florescent bulbs like most people get for seedlings. I was wrong. Apparently the lights need to be hung real close to the seedlings to work. The ones on the ceiling weren't helping at all. I was growing tall, weak seedlings. This year I got 2 different grow lamps and my seedlings are looking much stronger!
Not enough heat: I always started my seedlings on top of the refrigerator as I'm sure many people do. The problem was, my new refrigerator is no warmer on top then the rest of the room is. Seeds took forever to germinate, many just got moldy. I bought a heated seed mat and my germination rate tripled this year.
Horrible labeling system: Let me tell you something that will save you a whole lot of problems: most seedlings look alike. Don't be like me and expect to be able to tell them apart, or you'll end up with a zucchini growing in the pumpkin patch. (true story) Use a sharpie to write on craft sticks, write on the containers, make a list or separate them with different size or color pots. Whatever you decide on, just make sure it's an easy to understand labeling system. I know the extra steps may sound like more work then it's worth, but at least you won't have a pepper plant in the flower garden.
Using garden dirt: This was a bad idea for several reasons. Mainly it was bad because my garden soil is not all that great. It has some crushed sandstone and clay qualities that aren't ideal for delicate seedlings. I can mange it with lots of compost in the garden, but in those tiny pots it was just too much for seedlings to fight through I only made that mistake once. That was also the year I had weird dirt bugs appear in the house. Never again.
Cheap potting soil: The year after I tried starting seeds in dirt from the garden I decided I better switch to potting soil. I bought some pretty cheap stuff and those poor seedlings really struggled. I later learned that there probably wasn't enough nutrients in the soil to sustain the seedling for the 4-6 weeks before they were to be moved to the garden. Most of the seedlings were weak and grew slowly. They didn't transplant well either. I got much better results when I switched to a high quality organic potting soil.
Starting too early: I had a few years where I started seed so early they became root bound before it was warm enough to put them in the ground. Once they were in the ground it took them awhile to adapt and start growing again. I know it sounds like you'll get a jump on things by starting seeds extra early, but unless you have a really short growing season it's unnecessary and counterproductive.
Thankfully, it seems like my seedlings are all doing well this year. I have the herbs started now, but the veggies are next in line. Happy planting!
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