Seed Starting 101

Something that we have learned over the years is that healthy, sturdy transplants make a huge difference in the success of your garden. When we first started out our plant starts were not much to be proud of. They were usually tall and spindly and many of them didn’t survive being transplanted to the garden. It was discouraging to say the least.

Back when we were growing the market garden we began selling plant starts in the early spring to supplement our income from our veggies. We quickly had to learn and develop systems for the best methods for growing healthy transplants from seed.  At the beginning we didn’t really have a great place to start plants, so we ended up growing them next to every window in the house to take advantage of some natural light. However we soon discovered that it wasn’t enough and all our seedlings became spindly and leggy as they leaned toward the light.

4 Keys to Seed Starting Success

1. Soil blocks
2. Good labeling
3. Good lighting
4. Air circulation

We start all our plants in soil blocks that we make with a soil block tool. It compresses the soil mix into 1.5 inch cubes with an indentation on the top for the seed. Each flat holds about 75 soil blocks. We have found this to be a very efficient and economical way to go. We bought ours from Johnny’s Selected Seeds several years ago.

There are several benefits of using soil blocks over plastic starter cells. First it cuts down on plastic that needs to be disposed of at the end of the season. I always tried to reuse my plastice starter cells, but they never were in very good shape and it was more hassle than it was worth. Secondl using soil blocks creates healthier seedlings. When the roots hit the side of traditional cells, they begin to curl back around and become root bound. When the roots reach the edge of a soil block, the roots simply stop growing. The greater oxygen develops stronger root systems as well. And third, there is a much higher transplant success rate. When it is time to transplant the seedlings, there is less disturbing of the roots and, therefore, less transplant shock.

Overall, using soil blocks has been very beneficial for my gardening.

In the past we made all our own soil mix. For a large batch it is more economical and overall it is a better mix. Here is our recipe. For making soil blocks it needs to be very wet, but it also works well in cell packs or pots.

7 1/2 gallons peat
1/2 cup lime (mix with peat)
5 gallons perlite
5 gallons compost 
1 cup blood meal
1 cup phosphate rock
1 cup greensand
Mix well

This year for simplicity I am using a mix of half organic potting soil and half peat moss. There are new more sustainable options, but I already have a big bag of peat moss that will probably last me several more years. I added just a little bit of an organic seed starting fertilizer as well.

Once the block s are made one seed (two if it is older seed, then thin to one plant) gets planted in each indentation. I do not even cover my seeds. I used to cover them lightly with soil, then I started just gently pressing them in with the end of a pencil, now I just put the seeds in and it works fine. As I plant each flat I am sure to label what is planted where, You can use wooden popsicle sticks, plastic plant labels, cut up yogurt containers, or even stickers od the side of the flat. I always use a permanent marker to prevent fading! Good labeling prevents so much confusion later on, I know from experience!

After the flats are planted they go onto a designated flat surface. Where we live currently this is on my washer and dryer. Warmth and moisture are especially important while the seeds are germinating. We check the flats often to make sure they are not drying out at all. If you keep your seeds moist and warm they will usually germinate quickly and at a good rate.

We watch carefully for the first little sprouts to appear. As soon as they do light becomes very important! When we first started out we depended solely on sunlight from the windows, but it just wasn’t enough and that was the biggest reason for spindly, weak plants. I have a shop style flouresent light hung on hooks from shelves above my washer and dryer. Ideally ther is one cool and one warm bulb in the fixture to acheive full spectrum light. The light should only be a few inches above the seedlings and can be raised as they grow. Honestly my set up looks a little tacky but it works. When I am done starting seeds I am able to simply unhook the light fixture and store it in the garage.

The last thing that I have found to really help my seedlings is good air circulation. This helps the plants be a bit more sturdy and can help prevent problems with fungus and mildew. For this I just run a small fan on low across my seedlings. I probably only keep it running about half the time.

I start almost all of my own transplants from seed at this point. Most crops spend about 4-6 weeks in the soil block and then get transplanted directly to the garden. These include lettuce, broccoli, cabbage, kale, cucumbers, and squash.

Some crops spend 4-6 weeks in the soil blocks and then get potted into 4″ pots. These are mainly tomatoes, peppers, and basil.

The onions and leeks are done a little differently. They are scattered into a flat that is full of soil mix and grown in there until they are ready to separate out and transplant to the garden.   

I hope that this seed starting 101 post has been hepful! If you have any more questions or if I forgot anything please ask!