I somehow acquired the knowledge (article, conversation, dream? I really cannot remember, so if you told me about it, please let me know so I can credit you) about how one can seed out tomato and pepper seeds (the eggplant is my own experiment) into coffee grounds instead of seeding compound and I had to give that a try, what with having nearly unlimited amounts of used coffee grounds and no free seeding compound at all.
In order to do this I started saving the grounds separately sometime in January, rather than putting them into the compost heap as usual. I dried them out and eagerly anticipated March 12th, which is when I had determined I needed to seed out my tomatoes and peppers to have nice, healthy, large plants by the time they can go into the ground. I was a bit late and seeded the whole shebang out on March 15th.
I added some ground up eggshells to the grounds and just a teensy tiny little bit of Epsom salt to the water. This was supposed to make them stronger and come up quicker. I don’t think it did. This is somewhat disappointing since I had high hopes for this method. It is not however the end of the world. They are only a few days old and may still prove to be more vigorous than their brethren raised in regular potting soil. I almost wish I’d done a test seeding now.
Mmh, note to self: Self, next time, do a test seeding into regular seed pellets to check the results!
Today is March 25th, and the little tomatoes and eggplants have mostly popped up and put their little leafs out. The germination rate was as expected; almost 100% for the seeds acquired this year and about 80% for last years l eft overs, still waiting on the peppers. I am confident that they will come up, but have taken to calling them slackers at least once a day. If they do not (I’m giving them until the 28th before I abandon them to their fate and seed out replacements , at which point they will all sprout ) then I will have some slightly less advanced peppers.
Over all I have to say that next year I think I’ll try a mix of coffee grounds and potting soil or seeding compound, probably a 70/30 mix, heavy on the grounds. Also I think I’ll go to Starbucks for the grounds if they still give them out, rather than collecting my own. That took a lot of effort and counter space in the kitchen. I’ll continue to compost my grounds or use them when planting the tomatoes into the ground, as I have done in the past, since that seems to work rather well.
On a related note, I started rinsing out any eggshells I generate in the kitchen, dry them and grind them up to use as soil additive and over the winter we accumulated about a gallon storage bag full. That is well worth it to me. YMMV. There is a school of thought that uses the shells as seedpods rather than grinding them up. That seemed like too much effort for me this year, I may try it next year, though, since I am much intrigued by the idea.
One last thing I would like to add here is that for some reason (perhaps I should have baked the grounds at a high temperature to sterilize them or not kept them in a warm, dark place at first) I got a layer of mold on top of the ‘soil’ within a day of seeding out and wetting it. This does not seem to have affected the seedlings at all; the ones that have come up so far are strong and quite vigorous. It did give me quite a scare, though.
I combated this by taking the seed flats outside and setting them into the sun with the lids off to dry them out just a little bit, which seems to have killed off the mold. Thankfully we’ve had some very nice weather; sunshine coupled with temperatures in the 70s. If we had had less favorable weather I would have simply left them sitting on the sunny windowsill over the heat vent, hopefully achieving the same result. Next time I will definitely heat the grounds to at least 400F prior to seeding out in them.
Happy Gardening to all.