How to stop spinach bolting in a home veggie patch

Why spinach runs to seed, and what you can do about it

You go out one morning and the spinach has put up a stalk, and inside a week the leaves you were going to eat have gone tough and bitter. That's bolting, and it isn't something you've done wrong so much as the plant deciding its season is over and getting on with making seed, which is what a cool season crop does the moment it gets a hint that things are warming up.

What actually sets it off

Heat is the main one and day length is the other, because spinach reads longer days as a signal to flower whether the weather has caught up or not. Stress brings it on early as well, so a plant that dried out badly, or one that's been sitting in a crowded row fighting its neighbours for water, will bolt sooner than one that has been kept comfortable. That's useful to know, because heat is not something you can do much about and stress is entirely in your hands.

Sow it at the right end of the year

Spinach wants mild weather, so the two windows that work here are early autumn, which gives you leaves through late autumn and winter, and late winter into early spring, which gets a crop off before the heat arrives. Sowing it late in spring is asking for trouble, because the plants will be small when the first run of hot days turns up and they'll go straight to seed rather than bulking up first.

Pick a variety that holds on longer

English Medania is a slow bolting true spinach and it's the sensible pick for most home patches. Perpetual spinach is the other one worth knowing about, and while it's really a beet rather than a true spinach, it copes with warmth far better and keeps cutting for months, which is why a lot of people who have given up on spinach end up growing that instead.

Keep the roots cool and the water steady

• Get mulch on it. A good layer of sugar cane or straw holds the soil temperature down and keeps the moisture in, and it's the single most useful thing you can do for a leafy crop.
• Throw some shade over it. Shadecloth on a simple frame takes the edge off the afternoon sun and buys you a few more weeks of picking.
• Water consistently rather than heavily. Letting it dry out and then drowning it is the pattern that brings bolting on fastest.
• Give it room. Around 15cm between plants, so the roots aren't competing and the air can move through.

Keep picking

Taking the outer leaves regularly keeps the plant in leaf-making mode, and if you leave it alone for a fortnight it's more likely to decide it's finished. If you spot a stalk forming in the middle, snap it out straight away, and you'll usually get another week or two out of the plant before it insists.

Sow a bit at a time

Spinach will bolt eventually no matter what you do, so the real answer is to never have all of it at the same age. Put a short row in every fortnight or so through the cool months and there's always a younger batch coming on as the older one gives up, which turns bolting from a disaster into a thing that just happens on a Tuesday.

When it bolts anyway

Pick everything worth picking before the flavour goes, because the leaves get bitter quickly once the plant commits. After that you can either pull it out and put something warm season in the gap, or leave a plant to set seed if you want to collect it. Silverbeet is the obvious swap if you still want greens through the warm months, since it will sit there in weather that would have finished spinach off weeks earlier.

And if you're not sure whether what you're looking at is a bolting plant or something else entirely, bring a leaf in. It takes about 30 seconds to tell you at the counter and it saves you reading forum posts half the night.

Shop related products

• D.T. Brown Spinach English Medania. A slow bolting true spinach for the cool months.
• D.T. Brown Perpetual Spinach. Handles warmth far better and keeps cutting for months.
• D.T. Brown Silverbeet Fordhook Giant. The swap when it gets too warm for spinach.
• Martins Organic Sugar Cane Bale 11kg. Mulch to hold the soil temperature and the moisture down.

Did you know we cut shadecloth to length in the shop, from 50 per cent right up to 90 per cent, which is the cheapest way to take the heat off a bed of greens. It isn't on the website, so ring us on (08) 8536 4333 to see what's on the roll.

The garden centre carries the seed, the mulch and the feed for a leafy bed, so have a look through the garden range or come in and we'll point you at what's going in now.

Read next

• The hidden trick to growing perpetual spinach year round
• How to grow your own salad greens at home
• How to keep a garden alive through a heatwave

Spinach and I have an understanding, which is that it bolts whenever it feels like it and I pretend that was the plan, so a bolted row is no reflection on your gardening either.

Cheers,
Candeece