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.
- I took a plastic under-bed storage box that’s about eight inches deep.
- 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.
- 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.
- 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.
- And I got a cheap LED grow-light for about £40.
- 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.
- 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.
- 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.
- 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.
- 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.
Conclusions
I think this is one of those things that it’s quite easy to set up in a rough-and ready sort of way, which is my modus operandi, quite frankly. And harder to do precisely, which I have no interest in at all. My aim was to have fresh salad for the family that would survive even if I had three days unable to get out of bed and no-one else remembered to water it; and to avoid having half-liquid bags of leaves in the bottom of the fridge. I have achieved this.
The initial set-up cost was a bit eye-watering, largely because of the cost of the light. The ongoing cost is obviously the electric for the pumps/light and the Formulex, which costs about £5 per month, less if I change the solution every three weeks rather than two. You can make your own, but for me the cost offsets the faffing around.
Salad is £2 a bag and we buy a bag or more a week. So I’m £5 in hand a month and it will take two years to pay for the kit, ish. I’m happy with that—it wasn’t meant to be a cheap solution. I feel that I’m balancing my desire to have a proper permaculture garden and feed us all from scratch with what I can manage by myself with my physical and temporal limitations!
What I’d do differently
I’d probably not have such a deep container. For cut-and-come again and baby leaves, the eight inches isn’t necessary. Five would probably do, which would mean you could cut down on the clay pebbles needed, and therefore the amount of solution and the amount of nutrient.
These articles were helpful
- Building an Ebb and Flow bed: https://somegardeningtips.com/building-a-compact-ebb-and-flow-table/
- Starting Seeds for Hydroponics: https://www.epicgardening.com/starting-seeds-for-hydroponics/
- Why is EC important? https://www.hydroponics.co.uk/news/why-ec-is-important-in-hydroponics/
- PH and nutrient levels for vegetables: http://www.homehydrosystems.com/ph_tds_ppm/ph_vegetables_page.html
