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Image: Tina Tiller
Image: Tina Tiller

SocietyDecember 9, 2023

Their house, my garden: What to do when your plant is bolting

Image: Tina Tiller
Image: Tina Tiller

This week on Their house, my garden, why my spinach plant has grown suspiciously tall, and how to deal with your own over-eager plants.  

Beginner gardeners would be forgiven for thinking a plant growing tall is reason to celebrate. We are, after all, the kind of species who mark door frames with little lines to track our growth, strap thin sticks to our heels in efforts to look glamorous, overstate our height on dating apps, and sometimes even design our hair to give us extra inches on top. 

Plants, however, tend to do none of this. For some, it is good to grow tall, since there is pure un-shaded sunlight above everybody else around them. But those are only the plants that want maximum exposure to sunlight. Many prefer milder doses.

You may remember my bushy little spinach plants in their glamorous blue pot. Their leaves have been the basis of a few leaf pies and graced the inside of many a sandwich. At the front of the house, afternoon and evening sun blasts them for several hours a day, and because their pots are like a monocropped island, they have no tall friends to shelter or cool them. 

During the winter, they thrived. During spring, I noticed that their leaves had become tougher, started to taste funny and grown pointed rather than round. “I better move the spinach, it’s getting a bit blasted by the sun,” I thought. But alas, thoughts did not progress into action. Under my inactive watch, the plants have been growing taller, with a thick stem rising from their centres, a physical trait which spells their demise. 

Spinach running away via reproduction.

What is bolting and why does it happen? 

Since plants are stuck to the ground, growing tall is their only way of running away. I think this is why it’s called bolting. In my case, the spinach is running away from too much sunlight and a gardener that is apparently stuck in her own head. Sorry, spinach.

We’ve all seen the horror of the cordyceps fungi which turns ants into zombies that climb high, then cling on as the mushroom bursts from their heads and spreads spores far and wide. That is what the spinach is doing to itself. It’s run out of joie de vivre and is putting all its energy into reproducing before it dies. Flowers have formed on the tips of the new tall stems, and once they’ve been pollinated, will make seeds that will fall far and wide, by virtue of being high up (or at least high by spinach standards).

Only leafy greens and root vegetables bolt, since other plants flower to make their fruits. Some which are particularly susceptible to bolting are coriander, parsley, lettuce, carrots, basil, rocket and cabbage. Some bolt when the days get too long, or when they’re too hot or too dry or too cold. To some extent bolting is just a way of saying “going to seed”, which is a natural part of a plant’s life, but “bolting” suggests it’s been brought on prematurely by neglect. 

What can I do to stop it? 

To prevent bolting, you basically have to be a perfect gardener totally in tune with the climate and season, and able to exactly predict your individual plant’s needs before you select its location in the garden. Sigh. The next best thing we can do is try to water our plants well, and perhaps make tiny shade cloths if we suspect they’re getting too much sun. Surely some bamboo and a thin old pillow case would do the trick? Obviously, if they’re in pots, and you think maybe you should move them, you should.

Some bolters, like basil, can be kept in check a bit longer if you nip their flower buds early. Keep a close eye on them, and you will notice when their growing tips look different, tighter – snip them off. We should already be harvesting the growing tips of our herbs to encourage them to grow bushy instead of tall, but this particular method to fight bolting is called dead-heading. Alas, it will only delay the inevitable.

Once a spinach starts to bolt, there is nothing you can do to save it, and it will never taste good again, unless you like bitter stuff. Perhaps a case can be made for bolting spinach sbagliato, but it won’t be made by me. The plant is making itself taste bad on purpose, as a chemical defence against pests to ensure its seeds survive. It does raise the question of whether I am in fact a pest rather than a gardener. 

While you can’t save your spinach plant, there are still choices you can make about the bolting plant’s future. Ruthless and efficient gardeners will pull it out and probably chuck it in the compost bin (bolting is not contagious). They will not give it the chance to form seeds – if they can’t eat it right away, it’s got no value to them. Instead they will replace it, making the most of valuable garden real estate.

I’m of the variety of gardeners who will not do this. Instead, we will let those gangly stems rise, flower, dry out, and drop their seeds. In a few weeks or months, little baby spinach plants will unfurl their leaves. Everyone deserves to have babies if they want. 

Rather than calling them plants that bolt, we might think of them as self-seeding. It takes a little patience and some relinquishing of power and ego to be able to do this. You have to stand back and let the plant do its thing, even if it might reflect badly on you as a gardener. Adam Ben-Dror, the do-nothing farmer, would be proud of us, I think. 

Parsley grown from collected seeds going to seed.

Rethinking what plants are providing for us

Gardening is to some extent a cultivation, but it must also work with nature in order to harness it. I am always torn between wanting to tame things and wanting to let them be wild, wondering if what I think is tending to the plant is in fact just irritating it. Am I actually like Nosferatu, who picks flowers for his wife, only to have her say, “Why have you killed them, the beautiful flowers?”?

Plants, even in your own garden, do not exist wholly to serve you. They have their own plans and their own lives beyond your plate. You should be grateful it’s making beautiful flowers you can look at and smell. 

And, in this state you hadn’t planned for, you might also consider rethinking what you want from the plant. Like a tech start-up, we’ve got to be nimble and respond to challenges as they arise. Perhaps you’ve planted coriander, a particularly fussy princess of a plant. Yes, we all love a fresh topping of coriander leaves on our guacamole, or a bunch in our ph – but if the plant is going to give us seeds, why not eat them instead? They are the very same seeds you buy in little boxes from the spice aisle at the supermarket. Toast them and then sprinkle on top of things or put them into soups. If you’re particularly diligent, you could even grind them into coriander powder. Same goes for parsley seeds, which apparently also help you fart less.

Rocket flowers and seeds are edible too, though they’ve got a bit of a kick. Crush the seeds and mix them with cold water to make a mustard-like sauce. I’ve heard this was sought after in ancient Rome and Egypt, probably because they thought it was an aphrodisiac.

Radishes don’t often bolt, but when they do their flowers and seed pods can be eaten. They taste like radishes.

To collect seeds, wait and watch until the seed heads or pods are dry. Test if the seeds are loose with your finger (it’s better to wait longer and lose a few seeds to the garden than to be premature). If they are loose, cut the heads off and put them in a paper bag, then shake it. Collecting seeds will be a whole column in itself, but hopefully not too many things in your garden will go to seed until late summer, so we will wait ‘til then.

Top tip: Don’t be afraid to let plants do their thing. Maybe they don’t hate you, they’re just clucky.

Task of the week: Get out of your head and actually do the things you’ve thought you should do. Move your potted plants, confess your crush, go swimming.

Keep going!