Garden Tool Set

Mixed salad seedlings growing hydroponically, without soil.

Growing plants hydroponically, or without soil, is a clean, and resource-efficient way to successfully raise a variety of produce. Yet it seems to be viewed with a great deal of suspicion in many quarters. This extract, from Green Harvest, an Australian website, is reasonably typical:


"A large quantity of the salad greens available in the supermarket are grown hydroponically, the complete opposite of organically. Hydroponics is a growing system that bypasses the soil in favour of a 'nutrient soup' made from chemical fertilisers fed directly to the plants. The lettuces in the supermarket might look like a lettuce but chemical cocktail might be a better description."

I don't know what they put in bagged salad in Australian supermarkets, but I wonder what the author thinks soil consists of, if it's not a chemical cocktail itself.

Growing hydroponically isn't the "complete opposite" of organic growing. You can incorporate many organic elements into a hydroponic set-up - using organic coir as a growing medium, for example. I suspect that what makes people suspicious of hydroponic systems is the micro-managed nature of it.

What an organic philosophy and hydroponic growing have in common is the desire for sustainability. Both methods are far less fuel-intensive than using manufactured fertilisers. Organic systems aim to reduce soil erosion and exhaustion with the addition of organic matter; in many hydroponic systems, the growing medium can be reused many times. For example, perlite, the rock granules which are often used to anchor the roots, can be sterilised in a microwave and then used again for the next batch of hydroponically-grown seedlings. The micro-management that delivers precisely the nutrients needed to the growing plants also means there is far less waste.

If you look around on the Internet you'll find off-puttingly long lists of technical equipment required for a hydroponic set-up: pumps, filters, hoses, lights. You would be forgiven for thinking it's less like growing plants and more like a laboratory experiment.

However, much of the expensive and hi-tech kit is needed for hydroponic growing on an industrial or commercial scale. To successfully grow salad leaves an herbs on a windowsill, some pots, water and a soil-less growing medium is all you really need. And your 'nutrient soup' of course.

Hydroponics

+ Sustainable

+ Efficient use of resources - less waste

+ Takes up relatively little space, with high yields

+ Versatile – does not need fertile soil, can be grown anywhere

+ Cleaner to maintain

- Cannot be called organic
- Lot of management required to get the balance right

- Leaching if not managed properly

- Only suitable for some plants

We used a simple base kit from The Achiltibuie Garden. Based in the north-west highlands of Scotland, this company specialises in developing hydroponic growing systems for domestic use. Many of their systems are modular, so that you can add extra units to the base kit if your needs increase. This windowsill kit shown below, is good for raising salad cut-and-come-again leaves and herbs.

The kit: long plastic trough and four pots. The growing medium, a mix of perlite and vermiculite, containers with liquid nutrients and four packets of seeds.

The absorbent material which fits into the slotted base of each pot will take up water and the liquid nutrients into the pots.

The Secret Garden Club looked at the very wide variety of leaves available to grow yourself, and why you might want to do that.

First, some advantages of growing your own salad leaves:

You don't have to restrict yourself to pulling leaves from a lettuce - there are plenty of other types of salad leaves available.

Traditional lettuce – the type which you grow as single plants, spaced out, in order to mature and develop multiple leaves. You then harvest the whole plant at any one time.

Little Gem lettuce: succulent green leaves around a nutty tasting heart

This is a crop for the vegetable patch – lettuces need time and space. The best way to sow lettuce seeds is indoors in modules. Each plant can be planted out in the vegetable bed when the seedlings are big enough to handle. From the seed germinating to you eating a full-grown lettuce will take about 13 weeks.

Lettuce works best as a summer crop although they will appreciate some shade in high summer. For winter salads, I grow radicchio (see the picture at the top) and chicory. As with summer lettuce we sow the seeds in modules indoors in May-June and transplant the seedlings outside when they've outgrown the plastic pods. Both radicchio ad chicory have a robust, slightly bitter flavour, and can be cooked as well as eaten raw.

Chicory can be forced in the dark to make the leaves grow whiter, more tightly packed, more tender and less bitter. Grow your plants in pots, and in autumn, cut back any growth to leave a short stub above ground. Bring the plants indoors, somewhere unheated but frost-free - a garage, or cellar, perhaps. Place a bucket over each pot to ensure all light is excluded. It takes a few weeks, but the plants will send out white chicons, which can be cut and eaten as white chicory.

Cut and come again lettuce, also known as CCA, or Mesclun, or mixed leaves. This is a much quicker and more space-efficient way to grow lettuce: instead of thinning the seedlings and letting each plant grow to maturity, you snip leaves from the plants on demand - whenever you fancy a bit of salad.  This is a quick way to raise salad – you can be eating your leaves 4-6 weeks after the seeds germinate.

Sow the seed thickly in a container or in the kitchen garden and let the seedlings grow without any thinning. Once the leaves are a reasonable size, snip them off at the base with scissors. Don’t pull whole plants up – you want the seedlings to continue to produce new leaves after each harvest.

You can also grow different varieties in the same container so that you always have a mixed salad on tap.

What you won’t get is that lovely firm, nutty heart that you get in a Little Gem lettuce or similar. If you like lettuce hearts, like I do, it’s always worth growing a few for this alone. But my main salad crops are these, mixed leaves.

Lamb's lettuce growing in an old fruit crate.

Mixed leaves grow really well in containers (which whole lettuce plants don’t) and so you don’t need a garden at all. You can grow on a windowsill, indoors or outside – see the corn salad trough. You can grow in a reclaimed container – see the fruit crate.

You can mix and match varieties to your heart’s content to get the best taste possible from your salad or so that you can vary your salad flavours. At the Secret Garden Club we’ve got a standard leaf mix here and also an oriental mix here.

This crate was devoted to rocket, which is now well and truly in flower – don't let them go to waste, they're delicious and can be added to your salads too – and can be resown soon.

You may have seen these in fancy restaurants: tiny perfect salad leaves that still pack a punchy flavour. I suspect that if you’re trying to feed a family with salads that these may be too dainty but they’re useful to have around for a quick garnish.

All they are is seedlings. There’s no special treatment, it’s not like growing bonsais. You can use a shallow seedtray, or a small pot, because the plants won’t grow big enough to put down deep roots. Fill with seed compost, firm lightly and water. Sprinkle the seeds over evenly so that they rest in a single layer.

Cover v lightly with more compost. Then cover the tray – I’ve got the clear plastic lid but you could use a clear polythene bag – and place somewhere warm.

At this time of year, you’ll see the first seedlings in about 48-72 hours. Remove the lid but keep warm and sunny – a south-facing windowsill is ideal. The microleaves will be ready in about two weeks – again, this is a fast-growing time of year. In spring and autumn it will be more like 4 weeks.

Be brutal when cutting them for salad use, it’s not as though you’re growing them as cut and come again. Then resow – after only 2-3 weeks, you can re-use the soil.

Good for microleaves: coriander, most mixed salad leaves, oriental leaves such as mustard and mizuna.

Thinnings or leftovers from the vegetable patch made great additions to the salad bowl. Beetroot, chard, spinach and cabbage are all tender enough and tasty enough in seedling form to be used in salads. So when the time comes to thin or transplant the seedlings, don't throw away or compost the plants you thin out. Take them home, give them a good trim and wash and use in a salad.

This year I potted up the cavolo nero seedlings which didn't get transplanted into the main bed, transferring them instead into a 20cm pot with the seedlings evenly spaced out in it. These pot plants have leaves which are smaller, less fibrous and more tender, ideal for tearing up and using in a robust winter salad.

With beetroot, chard and spinach, I deliberately sow them thickly so that there is plenty of thinning to be done, and the thinnings always make up a nice spring salad. Similarly, when I transplant leeks the seedlings left over are delicious and delicately flavoured in a salad.

And don’t forget pea shoots. You can now buy these at great expense as part of a supermarket bagged salad – instead, why not sprinkle leftover pea seeds over a pot and use the seedlings for salads?

It also feels like food for free, which is always pleasing, as it’s kind of a by-product from another crop.

Salad of Little Gem lettuce leaves and nasturtium flowers (plus a few buffalo mozzarella pieces).

Edible flowers
We covered edible flowers in some detail at the Secret Garden Club in June. These are always good for adding stunning good looks and a delicate contrast in texture and flavour to a salad. Adding flowers to a green salad will immediately lift it out of the ordinary visually. Our post on edible flowers explains how to pick and prepare flowers for culinary use.

Nasturtiums, shown above, are first choice for adding to salads - and the leaves, finely shredded, will give any salad a good peppery kick as well. The flowers are plentiful at this time of year and are easily picked a separately to give salads a shot of hot orange or vibrant red.

Also good in salads are chive flowers, bergamot, violas and marigold petals.

Sprouting seeds

If we can have microleaves, I suppose these must be nano-leaves. Most people are familiar with beansprouts as bought in the supermarket, and possibly – if you’re feeling very healthy – alfalfa sprouts.

These are seeds which you sprout in water just to the stage of producing the first leaves, which can then be eaten raw or stir-fried. They have a delicious flavour and crunchy texture and add variety to salads. They are also highly nutritious - each sprout packing all the nutrients needed to grow the plant from germination to its first true leaves.

The beansprouts you buy most readily in the shops are grown from mung bean seeds, but of course you can experiment and find the ones you like the best.

I think mung bean sprouts can be a bit bland – my favourite for flavour are adzuki beans and also chickpeas – which can be quite large.

Here’s how to grow them. You will need a glass jam jar, with a fine mesh lid or covering. A cut-up square from a very clean pair of tights or stockings stretched over the top and secured with a rubber band is a perfect solution.

Rinse a handful of beans, drain well and put in the jar. Stretch the mesh over the top and secure - with a rubber band or similar. Rest the jar facing down at an angle so that any excess water drains away.

Twice a day, once in the morning, once in the evening, you need to pour water into the sprouts, either through the mesh or with the mesh removed. Then replace the mesh, swirl the water around to rinse the seeds thoroughly, and drain, resting the jar at a downwards angle again. The jar should be kept in the dark - but choose a cupboard you open and use fairly often or it's all too easy to forget about them!

Don't forget to rinse the jar twice daily or the seeds will dry out and not grow. Don’t forget to drain them after each rinse – if they sit in water they’ll rot.

The sprouts should germinate within a week. Use them when they about an inch or two long and before they grow their first leaves.

With a combination of all of these you can have salad on tap 365 days a year.