Hydroponics – the process of growing plants by applying liquid nourishment directly to their roots rather than via soil – comes in many shapes, sizes, and varieties. Here at HackSpace towers, we don’t have space to create vast amounts of produce, but would like a little fresh salad grown on our windowsill, where the pesky slugs that blight the garden can’t get at them. Can the simple kits available from direct-from-China sites help us here?
We turned to AliExpress vendor, Garden World Store, and purchased a twelve-holed bubble cabinet for £24.27. This is one of the simplest methods of hydroponics, where the plants are grown suspended directly in the water, and an aquarium pump keeps the liquid oxygenated. Other hydroponic approaches include trickling water over the roots, or applying a mist to the roots as they’re suspended in the air. In principle at least, hydroponic systems should allow plants to grow faster and with less intervention than those grown traditionally. They can also be grown more densely, which comes in particularly useful when space is limited indoors.
Pick of the crop
As we’re fairly literal-minded, we decided to test our setup with watercress. Hydroponic systems can grow a wide range of plants, but leafy greens are the easiest and quickest to grow, particularly in a simple system like this. They’re also a crop that can be expensive to buy and taste better when fresh, so make an ideal candidate for home cultivation.
There’s not too much to the assembly – essentially everything just slots together. To start your crop, first germinate some seeds (place them on a damp paper towel for a couple of days until they just start to grow, then transplant them to a foam plug (included in the kit) using the supplied tweezers). Leave these soaking in a small amount of water until they have three leaves, then fill up the tub with a water and nutrient solution (not supplied), and start running.
There’s no clear information on exactly how much bubbling the solution needs, as it’s hard to measure the amount of dissolved oxygen in water. It will vary, depending on the power of your particular bubbler, the strength of your plants, and a myriad of other factors, so you’ll need to experiment to get it right. We’ve combined our system with a simple timer switch that runs the bubbler when we’re least likely to be near it, (so the noise of the bubbles is less distracting).
As well as water and nutrients, plants need light. We’ve placed our system on a windowsill that’s in sunlight for most of the afternoon, and this is working well through summer. If you have less light – or for year-round growing – you might want to partner this system with a grow light to speed up growth. If you do, make sure that you get the right colour grow light for the crops you produce – the balance of frequencies can have a big effect on the plant, positive and negative.
Reap what you sow
Our setup is running, and we took our first crop just three weeks after planting out. We’re using a cut-and-come-again approach, where we harvest some of each plant and leave the rest to keep growing. This should mean that our system will continue to supply us with watercress for many months to come. We’ve found that now everything is going, there’s very little to do. About once a week we top up the water levels, but other than that, we’ve not had to do anything.
So far, this little hydroponic system has delivered a quick supply of salad in a small space with little effort – exactly what it promised to do. Hopefully it will mean that the days of getting halfway through a bag of salad before it starts leaking brown juice are behind us, and we will now subsist on a diet of fresh, green leaves. Whether this gives us better health for better making is still to be determined.
The hydroponics setup is made from cream-coloured plastic that does let a little light through (as opposed to the black plastic of many more expensive hydroponics setups). This hasn’t caused any problems for us, however, though it could lead to a build-up of algae in the tank over prolonged usage.
In the world of hydroponics, our setup is tiny, both in terms of the size of plants it can support, and the number of them. This is perfect for a few salad leaves, but it’ll struggle with larger plants. Make sure that you match the hydroponic system you get to the crops you want to grow to avoid disappointment.