Growing hydroponic greens

I’ve been meaning to write about my hydroponics bed for ages and haven’t got round to it. I started it in the winter and made a whole big deal about being able to grow my ‘Brexit lettuces’ because of the uncertainty about fresh food prices after the UK crashed out of the EU trade networks. It’s working pretty well now, so here’s a summary of what I did. It cost about £100 to set up.

1. I took a plastic under-bed storage box that’s about eight inches deep.
2. I fitted ebb-and-flow fittings in two of the corners—an in and an out. They’re also sold as flood-and-drain fittings. I paid about £12.
3. I repurposed an old waste bin as my water reservoir. You need something that will hold more water than your under-bed storage box and if you can rig up a lid that’s good because it stops evaporation. It needs to be positioned lower than your grow bed.
4. I bought a small air pump and a small aquarium pump for about £10 each. These both go in your water reservoir. The air pump stops the water going horrible.
5. And I got a cheap LED grow-light for about £40.
6. I filled the storage box with clay pebbles to about an inch from the top. Don’t do this until you’ve got it in situ because of the weight. Wash them first because they’re dusty and that clagged up my little pump.
7. I bought four-inch mesh pots and some flat trays. The mesh pots I use for tomatoes etc and the flat trays for green leaves. I use coir in the flat trays and a grow-sponge surrounded by coir in the pots. The flat trays are only half an inch deep and aren’t ideal. I need something longer and deeper and narrower to fit my set-up, but haven’t got round to making anything yet—I’m thinking that old plastic milk cartons with lots of holes punched in them might work. You need it to be net-like so the roots can work their way out. The pots work fine, I start them in the bed and then when the plants get tall I move them into large individual jars on the floor. This needs changing regularly because it goes green.
8. I use Formulex liquid, on a 1:10 ratio. So my set-up takes 20 litres and I put in 200ml of liquid and change it every two or three weeks. It costs £12 per litre.
9. I set the pump on a timer. Over the winter I had it going for fifteen minutes four times a day. Now it’s got warmer, I have it going for a extra two slots during the daytime.
10. The light I initially had on for twelve hours a day. BUT I didn’t get very good growth and so I kept it on permanently and the lettuce seemed to really like that. Now we have more than 12 hours daylight, I’ve turned it off completely.

I also used an old vivarium heat pad during the coldest months—the set up is in my conservatory which gets pretty cold in the small hours. I slid that under the box, on top of the wooden surface and it kept the heat of the clay balls up sufficiently that the water flowing in was warmed and wasn’t a shock to the roots. If you have it in the house where it’s doesn’t get too cold at night, you won’t need that.

I read up a lot on EC levels—the mineral and nutrient content in the nutrient mix. Different plants need different kinds. It baffled me, quite frankly—I include links below so you can be baffled yourself. By random luck I seem to have hit on something that lettuce and tomatoes love, so I just change the solution every two or three weeks and it seems to be working.