I am growing some onions from seed. I have never grown onions before, so this is definitely a learning experience.
I watched a good youtube series on the entire process, including when to pick them, and how to preserve them for storage.
I wanted to make my own seed starting mix this year, because last year my transplants weren't very healthy. The other thing I was hoping to create was a seed starter that I didn't need to add any fertilizers to. This is the soil mix that I came up with:
Homemade mix (approximate)
35% compost that I made last summer (manure + dry forest leaves + some grass clippings)
35% peat moss
20% perlite
10% play sand
I setup one seed tray with homemade mix, and another seed tray with a commercial seed starting mix that is made of peat moss, coir (coconut fiber), perlite, ground limestone, wetting agent, and mycorrhizae (fungus of some kind). I am growing two different types of onions, one is a standard large cooking onion good for storage, and the other is a perennial Japanese bunching onion (sort of looks like a green onion to me, it's supposed to divide and spread on its own). I split the seeds from each packet equally, and planted them in the trays. Each tray has 50% storage onion seeds, and 50% bunching onion seeds. The seed trays spent about a week in warm room with a seed heating mat, and a humidity dome. After they begun to poke out of the dirt I moved them under a grow light. Both trays are in the same location. I did my best to water each tray about the same amount, and kept the seeds moist through germination.
Preliminary observations between the two different seed mixes:
- The homemade soil mix appears to have a lot more things living in it, I have kept the soil moist since bringing it inside in the fall. It's been in a big plastic tub with a lid for a few months. I notice some pill bugs, a few small centipedes, and various other things crawling around. Unfortunately also some fungus gnats. It's a heavier mix, and that is probably because of the added sand component. It's a little harder making the holes for the seeds, as it's a bit more chunky.
- The commercial seed mix is very light/fluffy, and easy to work with, overall planting takes less time. Doesn't appear to have anything living in it, and it takes a little bit of time to fully hydrate.
I ended up planting over 250 onion seeds in many seed starting containers, with multiple seeds per pot. I planted the same number of seeds in each pot. There are many more pots, but I am only going to show a couple for illustration purposes. I am going to take a picture of the same pots each time I post an update. Below is a picture of each type of onion in both kinds of soil:
Bunching Onion
LEFT POT: Commercial mix - RIGHT POT: Homemade mix
Germination Rates
Commercial mix: 84%
Homemade mix: 81%
Observations:
If you look closely you can see the
onions in the homemade mix have grown their second leaves earlier than the ones in the commercial mix. Seedlings have a more difficult time standing straight in the commercial mix, could be due to the fact that it is very light. When watering the commercial mix I need to be careful not to wash the soil around in the pots, this isn't a problem in my homemade mix. Water rapidly soaks into the homemade mix, this takes longer in the commercial mix.
Storage Onion
LEFT POT: Commercial mix - RIGHT POT: Homemade mix
Germination Rates
Commercial mix:
46% (LOW!)
Homemade mix: 94%
Observations:
Shocking difference in germination rates, the commercial mix didn't even crack 50%. The onions in the homemade mix sprouted noticeable earlier, and appear to be healthier, with some seedlings starting their second set of leaves already.
Conclusions:
Really surprised there was such a difference in germination rates in the two different soils for the storage onions, the seeds were from the same package, so I really don't know why they appeared to hate the commercial soil so much. The bunching onions didn't appear to prefer either soil for germination. I feel the onions in the homemade soil are growing faster, as more onions are showing second leaves already, and overall they appear to be healthier.
Going forward:
I am going to fertilize the onions in the commercial mix with a standard seed starting fertilizer high in phosphorus. They appear to be suffering, and I wan't them to be healthy to plant in the spring. I will leave the homemade soil alone, and won't add any fertilizer to it. This will provide an interesting contrast, and I will see how closely my homemade mix holds up, compared to onions getting water soluble fertilizer. Will the compost be enough? I am still fighting the fungus gnats in the homemade soil, and have put more sticky bug strips to catch the remaining gnats.
I hope you enjoyed my show and tell.
