This is not me retelling a Biblical parable…
As I mentioned, I really wanted to mix up my own seed starter but had problems finding the right ingredients back in February. I ended up buying pre-mixed store brand stuff. About a month after purchasing it, our local co-op was selling Dr. Earth’s seed starter by the pound so I got a small bag of it to try out.
Recently, I was able to pick up the supplies I’d been looking for earlier in the year, so I mixed up a small batch of equal parts vermiculite, peat moss, and worm castings. I now had three different growing mediums to try out. Just for comparison’s sake, I used all three in my most recent seed sowing:
While you can visibly see the difference in texture here, the most obvious thing was the absorbancy of the mediums. I always water the trays the night before planting to give the soil a chance to settle. Basically, the store bought stuff doesn’t absorb water. At all. It was pitiful how bad it was. I’d noticed that this was happening on some level, but kind of assumed that all seed starting mixes behaved like that. Well, lesson learned: a good seed starting mix will be able to absorb water and keep the seedlings evenly hydrated. The store-bought crap just let water pool at the top and then get evaporated by the lights. Grr.
I have two 5lb bags of the stuff left, but honestly, I will not be using it. Maybe I can find my receipt and return it? Anyway, none of the seeds have started germinating yet, so I can’t say for sure how much this will affect germination rates, although I have a good hunch that the Dr. Earth’s and homemade mediums will produce more seedlings. I bought a bale of peat moss, and I’ll also be purchasing a bag of good compost or worm castings and some more vermiculite so that I have a big batch of what I need to make my own mix next year.
Little Home in the Big City 