Broccoli tray (20x10 in) Input
• Seeds (20g) – $1.23 (will drop to $.37 if I buy larger quantities and source from different place)
• Water (3/4 gallon) (may have been as low as ½ gallon because I didn’t track this very carefully)
• Miracle Gro (.5 tsp) - $.02
• Electricity (2.16 kwH) - $.24 (typically comes out to $.08 per tray but I only made 1 tray this batch)
• Non-Chlorine Recycled Paper towel (4 sheets) – $.06
• CapEx depreciation/cost - $.10 (this conservative estimate to account for all expenses, most of it is LED light depreciation)
Total: $1.65 (optimized version will be $.61 per tray)
• Edible microgreens – 150 grams (~5 oz)
• Root/seeds/paper towel for worm composting bin
Comparison to store-bought spinach
• Store bought spinach is $.34 per oz
- My microgreens are $.33 per oz to produce
This is still experimental and only my 2nd batch of microgreens ever, so there is still lots of room for improvement. My germination and growth rate were slow, so next time I’m going to try adding some weight to improve germination. I accidentally let the tray dry out slightly twice, which may have slowed down growth. Now I know I need to water these daily with the winter low-indoor humidity. I’m also not sure if I harvested these a day or 2 early. It was at the 14 day mark and they were under lights for 9 days, but I’m thinking with the cooler temperatures that maybe they should have gone longer. I’m still getting the hang of harvesting the greens and I think I’m cutting them a little high so I’m losing some stem weight. I’d like to get harvests over 200g per tray.
I noticed these were a bit more damp when I was harvesting them, so I think I might need to set up a computer fan to provide better ventilation next time. I’ve been relying on a fan I use for white noise when I sleep to blow on them for 8 hours a night, but I think by growing them hydroponically I need to better balance moisture and ventilation. I didn’t see any visible mold, but I did notice the tray smelled a bit more musty than the first batch I made in soil. Nevertheless, I’d say the experiment was a success, and with some tweaking I should be able to get the same output as using soil at a fraction of the cost.
Next, I will try increasing the seed density based on a video I saw as it might increase output per gram of seed. I also want to get proper hydroponic trays with holes instead of using the DIY drilled versions, which didn’t give me the greatest root structure.
In the future, I might try using a fine mesh screen instead of paper towel, but I don’t think it would be worth it without some kind of auto-watering system since there will likely be more evaporation. I could potentially double layer the paper towel and see if I can go back to watering every other day like I did for soil. Once I have some worm castings I will try making worm tea and using that as the fertilizer/watering source instead of the Miracle Gro.
Does this make sense from a financial perspective? I think it makes sense since I’m saving money on food (more so once I optimize my process), along with not needing to go to the grocery store or rely on the industrial food supply chain. I didn’t include labor because it’s so minimal per tray that it’s virtually non-existent, I’m learning skills, and I enjoy it anyway.
Does this make sense in a low energy-intensity future? I think yes. Keep in mind these were grown completely indoors, so this is a viable strategy year around in any location and does not take away from existing arable lands. It gives you access to the rich micronutrients in greens at a time (winter) when growing leafy vegetables is not viable. Additionally, these types of vegetables typically don’t preserve well because they lose a lot of nutritional value. I suspect that LED lights and some electricity will still exist in the future, but alternatively one could modify this strategy to do it outdoors with natural light (but then you will lose output to pests, weather, etc). I believe these are very water efficient, with less than a gallon of water needed per tray from seed to harvest.
The one thing that does concern me about the sustainability of microgreens is that they are extremely seed intensive. You can’t save seeds because you are eating the plants before they get to the flowering stage. I don’t understand seed propagation that well, so I don’t know how viable it will be in the future to use 20 grams of seeds to make 200 grams of leafy green vegetables. Google tells me that one broccoli plant can produce ~20 grams of seeds.
My worm bin has been chugging along with no issues. I still think I have another few months until I need to worry about harvesting any castings. One thing I have noticed is that there are some castings falling through one of the drainage holes on the bottom (the screen ripped off). I wonder if I could remove the screens on the rest of the drainage holes and get a continuous harvest of worm castings just from what falls through the bottom. Obviously, I will still eventually have to sift through the whole container to get the majority of castings, but for now it seems to fall through naturally. I don’t need very much to make a gallon of worm tea for microgreens. I thought the worms might try to escape out of the drainage hole, but it seems they exclusively climb the walls of the container towards the lid if they are trying to make a jail break.
I was reading some things about mushrooms and then saw that someone in their journal was growing them. At first, I was trying to figure out how to incorporate mushrooms into my apartment homestead system. I was thinking through how to keep them humid when it dawned on me that I already have an enclosed place that is perpetually humid: my worm bin. There are a few accounts of people having mushrooms spawn in their worm bins unintentionally, which is what gives me hope that this might work. I started with ordering one of those mushroom growing kits which already have inoculated substrate that I just plan on placing on the surface of the worm bedding. If this experiment works, then I might try to grow on coffee grounds as a substrate (they are already pasteurized so risk of contamination is lower) placed on cardboard on the surface of the worm bin.
Issues I foresee are that the air flow in the bin might not be enough because both worms and mushrooms breathe oxygen and exhale carbon dioxide (I could mitigate this by drilling more holes). The mushrooms could be contaminated by something else in the bin, although it seems like contamination is less common after inoculation. The worms could start eating the inoculated mushrooms, although I think this is unlikely if I have some barrier cardboard and because worms don’t like to feed on surface food. Another issue is that the bin could be too dark to get the mushrooms to effectively flower, but if that’s the case I could cut some holes in the lid and cover in clear plastic to allow more light in to the mushrooms (would also deter worms from being on the surface). If the first batch works then I’ll likely drill a hole in the side of the bin and glue an analog hygrometer so that I can easily see humidity levels of the bin without having to open it.
I don’t really eat mushrooms right now, but I will be happy to incorporate them into my diet if this works. I see them as a bonus crop that can give me more yield and fit into my system with virtually no extra labor or resources.
Quail are on hold for now. Although my friend wants to get them, I’m hesitant to commit until I know where I’ll be moving this summer. If it’s within driving distance then I may take the quail with me when I move. The plan would still be to raise them in her garage instead of my studio. I should have an update on these in the next few weeks. We did try some store bought quail eggs and they were delicious.
I’ve noticed there really is a lack of resources for people trying to homestead and do biointensive food production on <1000 sqft of space. It seems the “urban permaculture” sites I’ve seen online and in books are usually 1/10 to ¼ of an acre, which to me is more like a suburban space. Conventional apartment gardening advice just talks about how to grow a tomato in a balcony container, but doesn’t really put any systems thinking into the process. Maybe there’s an opportunity for a blog or Youtube channel to fill the void, because I know most people live in urban areas and yet I see so little of permaculture implemented anywhere smaller than a suburban lot.