21 February 2020

How we protect our Kitchen Garden crops

From carnivorous plants to cabbage collars, find out how we protect our veg from pests in the Kitchen Garden.

By Hélèna Dove and Ellen McHale


Humans aren't the only creatures who enjoy fruit and veg. 

We use ingenious ways to protect our precious crops from hungry birds and insects.

Pigeon pillage

Pigeons are our main problem. Their favourite Kitchen Garden snacks are peas, brassicas and lettuce. 

To keep the peckish birds at bay, we surround the vegetables with netting and grow particularly vulnerable crops like lettuce in netting cages. 

We make the structures quite tall, because if pigeons land on top of the netting they can push it down and break in. 

Netting also keeps out other unwanted visitors, such as the cabbage white butterfly (Pieris rapae). 

The netting prevents these sneaky butterflies from laying their eggs on brassica leaves. This can be disastrous for a cabbage crop, as the caterpillars produced from the eggs can decimate a plant overnight. 

Kitchen Garden
Kitchen Garden, Andrew McRobb © RBG Kew

Cabbage collars 

Brassicas in the Kitchen Garden are also vulnerable to cabbage root fly (Delia radicum). The flies lay their eggs near the roots and when they hatch they burrow down, eat the roots, and kill the plant. 

We use cabbage collars which we place around the stem of the plant at soil level. This is a barrier that fits around the stem of the cabbage and stops the larvae getting from the soil to the cabbage plant. 

A cabbage collar in the Kitchen Garden
A cabbage collar in the Kitchen Garden © RBG Kew

Access denied 

Our carrots face a specific problem. 

Carrots suffer from root fly whose larvae eat the edible carrot root whilst it's in the ground. They also go for our parsnips.

This female fly doesn't travel higher than 60 centimetres, so surrounding the crops with a mesh that is 70 centimetres high stops them accessing the plants. 

We also grow resistant varieties such as Carrot ‘Resistafly’, which reduces the threat of root fly. This variety isn't attractive to egg laying flies and the larvae don't grow well on them.  

Parsnips, Kitchen Garden
Parsnips, Kitchen Garden, Ellen McHale © RBG Kew
Carrots fresh out of the dirt
Carrots grown at Kew

Aphid attack 

Like most gardens, the Kitchen Garden suffers from aphids of all shapes and sizes. The easiest way to remove these is by hand, or spraying with a hose pipe.

Insects such as ladybirds and hoverfly larvae are our friends. They like to eat aphids, so we encourage them into the garden with companion planting techniques.

This is when plants beneficial to each other are planted in close proximity. Marigolds (Calendula) are particularly good for attracting ladybirds, so we plant lots of them throughout the garden to appeal to our spotted friends. 


Helpful carnivorous plants 

We grow seedlings in our greenhouses behind the scenes, and when the plants are strong enough we plant them out in the Kitchen Garden beds.

The greenhouses protect the seedlings from the elements, but sometimes there are occasional attacks by sciarid flies (Bradysia) which live in the damp compost.

The larvae of these flies will attack the young vegetables, munching on roots and emerging leaves.

We use a carnivorous plant, Pinguicula moranensis, which traps the flies on its sticky leaves and protects our precious seedlings. 

So from netted cages to carnivorous plants, a varied approach keeps the pests at bay and is essential for keeping our fruit and veg healthy and thriving. Head down to the Kitchen Garden in spring to see our crops for yourself. 

Pinguicula moranensis in the greenhouses
Pinguicula moranensis in the greenhouses, Ellen McHale © RBG Kew
View along a vista with the Pagoda at the end and lined by trees

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