Starting seeds seems like such a wonderful idea. Put the seed in the soil in a small pot or cup, water and voila! Plants! Well… not quite. Seedlings can get leggy, die off easily, become yellow, become purple, loose leafs and the worst? Die.
With my first round of starting seeds for the most part in the past, I wanted to discuss my biggest mistakes, the ones I fixed and the ones prevented. Because the truth of it is, mistakes will happen – it’s how we learn. In the true agriculture way I’ll say the common motto – there is always next year.
Light
Early on after your seeds germinate, you need to make sure that they receive an adequate amount of light. Many times people will set their little seedlings in front of a south facing window in order for them to receive as much daylight as possible. If you’re in a northern climate, like myself, the amount of daylight during those early spring months is, well, insufficient in most cases.
My best recommendation is to get some form of supplemental light. I personally choose specific grow lights in order to be guaranteed that I was supplementing the right type of light. Many people use fluorescent shop lights which is a really efficient method however… I wasn’t prepared with that knowledge while I was in the store… so grow lights it was! Make sure to keep the light close to the plants to help prevent legginess!
However, these lights don’t let your leaves really build up their protection against harsh run UV rays. My biggest tip regarding light for starting seeds is to get them started well under grow lights/shop lights and then transition them to a south facing window once daily sunlight gets stronger. This helps your plants to start the hardening off process by becoming accustomed to the suns rays. See more under the “Hardening Off” section.
“My biggest tip regarding light for starting seeds is to get them started well under grow lights/shop lights and then transition them to a south facing window once daily sunlight gets stronger.”
Soil
Do not, I repeat, do NOT use garden soil. Garden soil is not free of weeds, diseases, and it compacts so easily. If you find some strategies about using garden soil, make sure it contains some type of process to sterilize the soil such as baking it. I personally use a general potting soil by ProMix which you can find at many home and garden stores or online on Amazon.
Water
This can be so difficult for new seeds starters. In fact, it was one of my biggest mistakes year one – I watered WAY too much! Overwatering your young plant starts can easily result in plants that become yellow, loose leaves, or become spindly.
My biggest suggestion is once your seeds germinate and gain their first set of true leaves, really back off on watering. Watering from the bottom is great, but you only want to give the plants just enough water that the soil will soak up. Water sitting in the tray isn’t great – this is where I went wrong. With many of my other house plants, I just filled up the bottom reservoir and called it good… So for weeks, I had water sitting in the bottom of the tray about 70-60% of the time which resulted in some yellowing. Once I figured that out, I only watered when the soil started getting drier.
Nutrients
This was my absolute biggest mistake the first year I started seeds. I had planted in ProMix general potting soil and about a month after I had started my tomatoes, I noticed that the oldest leaves would yellow and fall off. And then the next oldest leaves would yellow and fall off. Coupled with the fact that I was overwatering, this made for a bit of a mess. I fixed the overwatering problem first and still had yellowing leaves that would die and fall off.
I thought about it a bit and realized how much tomatoes must be nutrient hogs with the amount of foliage they produce. And foliage means they have a large nitrogen requirement… and I hadn’t fertilized them yet. Duh (face to palm moment). Now preferentially, I would have chosen to use a more natural fertilizer, but my plants needed help and fast so I went with an all purpose fertilizer by MiracleGrow. I mixed it up to about half strength and gave my tomatoes a solid watering. To my surprise, some of the leaves that had just recently turned yellow started transitioning back to green. Success!

Hind sight is 20/20 – after my plants had reached a point where they just started getting yellow leaves, I should have gave them a half strength fertilizer and routinely did that every 1-2 weeks depending on growth. You live and learn, right?
Hardening Plants Off
My personal opinion is that a lot of people make the hardening off process way too complicated. “Set them out for 1 hour, then 2 hours, then 3, 4, etc. until they make it a whole day.” Let me put something out there… I don’t have time for that! And I don’t really think most people do.
Mine did just fine by starting with placing them outside on a few nice days after I got home from work and bringing them back in. I also coupled this with placing some in a south facing window during the day.

After around 3-4 days of this, I just placed them outside in a spot that received sun for about half the day and then became shady. This works great for those who work during the day – less hassle! I only really did this when the South Dakota wind wasn’t treacherous though (so less the 20 mph). With this method, they become more accustomed to the environment without sun scalding.The last day or two before transplanting them, I just place them in more direct sun. Throughout the process I would always bring them inside at night.
So my first year starting seeds, I ran into a few problems that left me with a couple big tips that most people leave out in their seed starting guides- don’t over water and remember to feed your plants (but not too much)! I’m sure I’ll come up with some more with the passage of time, so stay tuned!
And remember – there is always next year so focus on learning and growing!