The problem with having virtually no garden and growing in containers, is the amount of compost you have to handle in a season. I recycle spent compost, add some nutrients and it has usually been fine but I can’t get away with it with everything. Plants like tomatoes, courgettes etc. are thirsty, hungry, feeders, so I prefer to give them fresh, good quality tomato compost from tomato grow bags but finding an easy way of keeping everyone happy isn’t always easy.
I have been growing tomatoes in a hydroponic tank for a few years now and the only appreciable difference I find in it from growing in compost is the plants in the tank are much stronger. Their stems are generally twice as thick as their compost grown counterparts. There is no difference I can find, with taste. The downside is having to keep the tank topped up, it’s just a basic tank without any watering regulator.
Now for this year’s new venture, it’s the Kratky system. It’s still growing plants in water but there is no need for aeration, as long as the water only comes about about a quarter of an inch above the bottom of the cup, leaving an air gap above it. Leafy vegetables can be grown in any container which holds enough water, hydroponic feed is added and light excluded. I already have hydroponic feed for the tank so no need to buy anything extra.
I have Mason jars and I ordered net cups which I thought might fit them, however I mis-judged the size and the cups were too big. Not to be daunted, I ordered more but as it turned out, it was the same size. I couldn’t get the right size so decided in the end, to make my own.
I have a few favourite cheap and cheerful accessories for early planting, such as plastic drinking cups, five-litre water bottles and a metal barbecue skewer. Simple things like that can see you right through to final plantings without spending too much money. The plastic cups, although still a little bit big, did fit inside the Mason jar. With the skewer heated on the gas hob, I managed to make net cups from the drinking cups. Turning a five-litre water bottle on its side, then marking circles using the net cups for size, I cut, or rather melted circles out of one side of the bottle.
The plastic sacks which originally contained compost are printed on the outside, but black on the inside. They are useful in many ways but for my purpose, I cut it to cover the bottle, cut the circles to match and that gives me a two-plant hydroponic planter.
My drinking-cup, net cups are deeper and more tapered than commercial net cups, but fit a wider variety of jars.
My lettuce seedlings were getting devoured by slugs and out of a whole potful, I was left with three healthy little plants. They have been transferred already into the hydroponic jars and held in place with a few clay balls. The black plastic cover is held on with parcel tape or elastic bands so that it can be removed to check that the roots have still enough water.
This method may change a lot of my growing although I will need to keep buying compost to keep my stocks of heavy black plastic healthy. My home-made net cup fits nicely into a coffee jar and the commercial net cup fits into a garden jar which once held fairy lights.