CHAPTER 7
May

By May, any local pests that you might suffer from (ants, aphids, slugs, and so on) are back in action, so you might need to think about ways of dealing with them (or just learn to live with them). This is also the time of year when you’re most likely to be overrun with seedlings and looking for homes for them – have you considered a little guerrilla gardening to spread the gardening love a little?

My Balcony at the Start of May

Plants and seedlings:

Herbs: sage, mint, rosemary, bay, thyme, chives, oregano, basil, parsley.

Peas and beans growing nicely up their poles; mangetout beginning to grow.

Pot of microgreens turning into macrogreens.

Bronze arrowhead lettuce.

Ruby chard.

Tomato seedlings, both inside on the window ledge and outside in pots.

Two pepper seedlings inside on the window ledge.

Carrot seedlings.

Potatoes.

Seeds and cuttings:

Courgette seeds inside on the windowsill.

Dill seeds outside.

Second batch of carrot seed outside.

More rocket and mispoona seeds just starting to germinate.

Alpine strawberry seeds – no sign of life yet.

Marigold and nasturtium seeds scattered throughout various pots.

Miscellaneous other:

Worms producing plenty of compost.

Things to Do in May

Microgreens and Baby Greens

Microgreens are the first few small leaves of lettuce, rocket, and similar green leafy plants, harvested when they’re only 2.5cm or so high. Baby greens are the same plants a couple of weeks later, when they’re maybe 7.5 to 10cm. After that, they turn into grown-up vegetables. Happily, they’re edible all the way through this process, so if you miss the boat for harvesting them as microgreens, you can still eat them a bit bigger!

Microgreens are ideal for growing in small or shallow pots or in small spaces, because they don’t have much in the way of a root system and they need very little space between plants (as you’ll harvest them when they’re still very small). This means that you can grow them in quite shallow trays, and fit them into whatever corner you have available – a windowsill or outside. You can use empty plastic packaging – the sort of plastic pot that tomatoes or grapes come in is ideal. These cartons won’t last long as the plastic is quite weak, but they’Slugs and snailsll certainly do at least one batch of greens. Punch five or six drainage holes in the bottom, fill with compost to an inch or so below the top, and use the lid of the package as a drip tray.

Baby greens in a pot that I later planted a tomato into.

Alternatively, if you have pots hanging around waiting for something else (e.g. tomatoes, peppers, courgettes, or anything else that needs a warmer time of year before being planted out), you can grow a crop of microgreens while you’re waiting for the weather to improve. Once the bigger plant is ready to go in, either harvest anything that’s left, or clear a space in the middle of the pot and keep growing the greens around the edges. I’ve also grown microgreens in the space around pea plants.

The small quantity of space taken up by a tray of microgreens also means that they’re great for keeping a supply of greens growing during the winter on a windowsill.

What and how to sow

Which seeds to grow depends on what you prefer to eat. A good idea is to sow a mix of different leaves that go well together. Cress, mustard, radish, and rocket (which comes in various different forms, all of which are tasty in different ways!) are all quite spicy, so you could mix up a bag of those seeds, sow them all together, then harvest them together. Mizuna, kale, and various sorts of lettuce are milder, so you could mix up a separate bag of those seeds for another set of trays. As a rule I just use whatever seeds I have hanging around – usually a mixture of rocket, pak choi, bronze arrowhead lettuce, and mispoona or mizuna.

Whatever you use, sow the seeds fairly thickly (they won’t get big enough to worry about overcrowding) and scatter a thin layer of soil over them. Water in well.

Care and harvesting

Keep the soil moist, but not too wet while the seeds are germinating. The first set of leaves you’ll see when the seeds start to germinate are called the ‘seed leaves’; the earliest you should harvest your microgreens is when the next set of leaves, the first ‘true leaves’, grow. Snip them off with a pair of scissors (to avoid disturbing the other shoots around them) and eat.

Unfortunately, microgreens aren’t cut-and-come-again, as they’re effectively just sprouts at this stage, rather than ‘real’ plants. To extend their lifespan a bit, you can leave some of the plants to grow a little bigger, for example, harvesting every other plant as a microgreen, and then harvest what’s left as baby leaves. Note that if you’re growing them in a shallow tray, you won’t be able to leave them much longer than this, as they’ll need more room for their roots as they grow, and will tend to bolt. Keep a close eye on them and be ready to harvest them – in warm weather in particular they grow very quickly! Also, the bigger they get, the more water they need.

If you don’t harvest regularly, the plants will bolt rapidly, especially if you’ve sown thickly and in a shallow tray. Make sure you keep an eye on the plants and are prepared to eat a handful or two of leaves on a daily basis.

Keeping a supply and seed saving

The easiest way to keep your supply going is to succession sow: just sow another tray every week or so. As a rule, microgreens take a couple of weeks to germinate and a couple of weeks to grow. In the winter, both stages may be longer (sometimes much longer, depending on where the plants are and how warm your house or windowsill is). Once you’ve harvested one tray, as long as there were no signs of disease in the plants, you can reuse soil and tray for the next batch (yank out all the old roots first); so once you’ve got started, you can keep a supply going for as long as you remember to keep sowing.

Unfortunately, you won’t be able to seed save, because you’re eating your plants before they get anywhere near the flowering and seed setting stage. You can either just keep buying seeds, or move a couple of plants to a full size pot elsewhere and allow them to run to seed in due course (the cheaper and more sustainable option). A couple of rocket plants allowed to run to seed should produce more than enough seed for the next season.

Pests

You’re not the only one who’s keen to eat the plants that you’re growing. There are plenty of other beasts out there that are also eyeing up your crops, and are happy to compete for them. You’re likely to suffer slightly less from pests when container gardening, but anything airborne (except carrot fly, which sticks close to the ground) is potentially capable of making its way even to a high balcony, and if you’re growing on a patio, even low level pests are likely to be around.

If at all possible, the ideal solution is just to live with them. If you’re only losing a few leaves here and there, see if you can simply tolerate that, rather than waging war on insect life. You’re highly unlikely to win in the long run, even if you’re prepared to use the full chemical arsenal available to the modern gardener and abandon the idea of organic growing. Insect life is also beneficial to the overall ecosystem of the garden.

However, if it really is a bit too much, here are some (organic) tips to redress the balance.

Aphids

Aphids, also known as greenfly or blackfly (these are different aphid species, but the differences aren’t important for our purposes) can be a big problem for gardeners. This is particularly true if you have an ant colony in the area, as the ants will sometimes ‘farm’ the aphids, protecting them from predators and encouraging them towards the juiciest plants, then ‘milking’ the aphids for the honeydew they produce. This is impressive behaviour on the part of the ants, but irritating for human gardeners! If this happens, you’ll wind up with far more aphids than you would normally expect, and the concentration may be enough to kill the plant. (For discussion of dealing with ants, see below.)

What aphids actually do is to settle on the plant and suck the sap from it, which damages and weakens the plant. It also distorts the leaves, which makes it difficult to spray them (see below) as the aphids are protected by the curl of the leaves. In theory, aphids won’t actually kill a plant, but if the infestation is bad enough, such as when the ants get involved, it can weaken the plant enough that it does die.

In my experience, the most popular plants if you’re an aphid are broad beans, mizuna, and rocket. Other lettuces can also fall victim, but they do seem particularly enthusiastic about rocket, especially once it’s gone to seed. Chard, once flowering, is also popular. My own favourite lettuce variety is bronze arrowhead and my local aphids seem (much to my pleasure) to be entirely uninterested in it; so if you do have problems, it may be worth experimenting to see what is and isn’t high on the local aphid preferred food menu.

As a rule, an excess of aphids indicates that there’s something not quite right in the local ecosystem. This is all very well in a garden or allotment, where you might expect a fairly varied ecosystem and where you have more scope to encourage other insects, but if you’re using a small balcony or roof it may be harder to deal with the problem by rebalancing the ecosystem. There are however still some possible steps to take to encourage natural predators.

You can encourage ladybirds by constructing a bug box (see below), by buying ladybird attractant sprays, or by sowing plants that ladybirds like. These include fennel, dill, and coriander – all also useful herbs! – and scented geraniums. However, this is a fairly long-term strategy; and you need to remember that while ladybirds may control aphid populations, they won’t actually get rid of them.

Lacewings, wasps, and hoverfly larvae also eat aphids. You may not want to encourage wasps (although it’s good to know that they do have a useful purpose in life), but you could consider encouraging lacewings and hoverflies. Lacewings like plants that are rich in pollen and nectar, such as rosemary, comfrey, thyme, mint, and sage. Hoverflies like marigolds and nasturtiums. These plants are also useful for other reasons, so are a good choice for a limited space. Bees will of course also be encouraged by all nectar-rich flowers, which is good news for all sorts of reasons.

All of these insects are also good to encourage for pollinating plants that require it (such as courgettes). Bug boxes can also provide shelter for endangered insect species such as stag beetles. Again, though, whilst encouraging these beneficial insects will help things back into balance, you’ll need to learn to live with a small population of aphids, or there will be no food left for the good insects! It’s about finding, as far as possible, a sustainable balance.

There are also short-term solutions available if you have only a small number of aphids. The most common is to spray them with a mixture of washing up liquid, oil, and water. This isn’t really a long-term solution, though, unless you want to spend a lot of time spraying your plants. Plus, your rocket will taste of washing up liquid.

Here are a couple of easy ways to provide insect homes (bug boxes) even on a small balcony:

  1. Bundle up some twigs or bamboo canes (cut them short to keep them manageable) and tie them up with string, then hang them up under a railing. I’ve done this on my balcony.
  2. Cut off the bottom of a plastic drink bottle, make holes in the sides, and fill with dead leaves. Leave it somewhere damp and shady.
  3. Fill a small plant pot with leaves, turn upside down, and put it somewhere damp and shady.

A bug box on the underside of my balcony rail.

Slugs and snails

One of the great advantages of growing plants in pots is that it makes it much easier to deal with slugs and snails. Simply put copper tape around the rim of each pot, and the arthropods won’t bother your plants. However, be warned that they can be quite persistent – a friend found a snail that had climbed up a neighbouring wall so as to drop into her copper tape protected plant pot from above!

Copper tape is also quite expensive. If you’re growing on a balcony, you may not need to bother at all – I’ve never seen a snail or a slug on my first floor balcony. However, this may depend on what the surrounding area is like (there is no snail or slug habitat underneath my balcony from which they might climb up).

A lower-tech option is to install slug traps, usually containing beer (sometimes known as a ‘slug pub’). The downside to this is that you need to get rid of the bodies of drowned slugs afterwards. They also work better if embedded in the ground, which obviously doesn’t work in a paved area. However, there is an alternative model of slug trap which uses a plastic bottle and which works even on a hard surface. Cut off the top third of the bottle, invert it, and insert it into the bottom section, so it funnels down into the rest of the bottle. Part fill it with fresh beer, and the slugs can climb up the outside to get in, but won’t get out again. (A similar idea works if you’re having problems with wasps, using a water and sugar solution with a smidge of washing up liquid.)

Slug nematodes are also available – these are little parasites that you water onto the soil, which the slugs ingest and then slowly die from. They can be ordered online from various garden sites, and are certified organic. In my experience they do work, but you need to keep applying them fairly regularly, and they’re probably overkill for a container garden.

Caterpillars

I regularly find that in mid/late summer, my green leaves acquire a huge number of caterpillars, which can destroy a window box of rocket or lettuce in very short order. Unfortunately, the only way I’ve found to get rid of them is to look for them, pick them off, and throw them somewhere else (a nearby municipal flowerbed, usually). Different species of caterpillar will go for different leaves, so growing a variety may help to reduce the carnage.

I’ve also seen a neem oil spray suggested to discourage them (though haven’t yet tried this), or a spray of cayenne pepper, water, and a tiny bit of soap to bind it. Obviously, if using this you’ll need to make sure that you wash your greens before eating them yourself.

Birds

Birds can be a major hazard to your crop, especially if you have fruit; and they may try to eat seed if you don’t bury it well when sowing. CDs or other shiny or noisy dangly things hung from above may scare them off; or you can net your plants, or even the entire space if it’s small enough. Again, this is less likely to be a problem on an urban balcony (my local birds seem to prefer to stick to the park).

Ants

Ants can be a huge nuisance, particularly if coupled with aphids. Unfortunately, getting rid of ants is extremely difficult, especially if you want to do it in an organic way.

If you can track the nest down, repeatedly disrupting it may cause the ants to pack up home and move elsewhere. Flooding the pot where you think they’ve set up home may cause them to clear out; make sure as well that there’s nowhere else in your space that is hospitable for them. Or you can take the plant out of the pot and shake the nest out (somewhere far away from your own space).

The old fashioned solution of pouring boiling water over the nest is also an option, although it’s cruel, it’s not clear how well this actually works, and it certainly won’t do your plants any good if you pour boiling water over their roots. Using boiling water to disrupt scent trails can be helpful, though; just pour the water over, let it dry, and repeat a couple of times. With luck, again, the ants will pack up and find somewhere else to live where their roads aren’t regularly destroyed.

You could try flour sprinkled around the base of the pots to put them off (it clogs up their exoskeleton and prevents them from taking oxygen in), but it will of course wash away and/or make a terrible mess when it rains. A little cinnamon sprinkled around where you’ve seen ants also apparently works well, as it will disrupt their scent trails, and again, will tend to cause them to pack up and leave. I tried this together with flooding them out when I got ants on my balcony, and found that it worked temporarily, but that I had to reapply the cinnamon several times.

If remotely possible, the best and easiest option is to learn to tolerate the ants – live and let live. Having said that, if (as with my local ants) they invade your wormery and kill all the worms, you may feel more like declaring war. If I ever win, I’ll let you know...

Guerilla Gardening with Unwanted Seeds

It’s usually around this time of year that you discover that you have a handful of spare seedlings, or half a packet of spare seeds. (Some seeds will keep until the next year, but not all of them – carrots are a notable case of seeds which simply won’t keep, so you may as well either sow or find homes for all of your seeds.)

You can just throw them away, but I always find that wasteful (and sad, in the case of the seedlings). Friends may be interested in doing seed swaps, or you may be able to palm off seedlings on them to encourage them to start doing a little gardening themselves – feel free to chuck in a copy of this book! Local garden or allotment clubs may also organise seed or plant swaps (try an online search for local garden clubs in your area).

Alternatively, you can do your bit to brighten up your local area, and do a little guerrilla gardening. There’s more information on this on, but the basics are: keep an eye out for neglected patches of earth around your local area, then get out there and send your unwanted seeds and seedlings out into the world.