Cutworms & Gromix

June 15, 2011 § Leave a comment

Two quick notes, firstly, here is a cutworm nestling happily in my favourite flashy butter oak lettuce.. get out!! (I fed it to the pig ha!)

Cutworms are usually grey-brown, but may have a yellow or green tint to them, and look like fat, smooth caterpillars. They measure about 2.5-4cm (1”) long and move very quickly when disturbed, curling up into a tight ‘C’ shape.


They reside in the soil by day and come out at night to wrap themselves around the base of plant stalks and eat them. They can decimate a crop and are partial to a wide range of fruit, vegetable and ornamental plants.

The eggs are laid by turnip moths in June and July. After two weeks the larvae hatch and live for a month before pupating in the soil. A second generation can hatch in August and September which will over-winter in the soil, coming to the surface to feed when environmental conditions are favourable.

Birds, especially chickens, feed on cutworms, and some nematodes will effectively eradicate them. A ring of twigs driven into the ground, tin cans with both ends cut off, cardboard or foil can be wrapped around the base of plants to prevent these soil-dwelling pests reaching the stems- mulch mats also.

My next comment is about growing media. Her eis the standard mix we use at

.. basically we need to get out of this antiquated mindset that plants need peat. Some plants do need peat- they thrive in it and substitutes often give substandard results – but these are very few. If your sowing seed or potting on plants you need not use pure peat/compost.

Free respiration in the root zone is essential for healthy, fast-growing plants. Plant respiration relies on air spaces in the soil for gaseous exchange to and from roots. The higher the porosity of a soil, the greater it’s potential to move water and air to plant roots. Smaller pore spaces mean greater water retention and therefore lower air supply.

In the image above you can see lots of aerators (along with peat-free organic compost) .. perlite and clay pebbles give the soil a lovely loose, airy structure. Sometimes we use water-retentive gel (about 10-20%) in the mix. This is a standard mix for potting on nearly any plant. For sowing seed we cover them with pure compost or vermiculite, but they are sown into this mix.

In the garden, coarse organic matter (leaves, pine needles, well rotted wood chippings etc) increases the size and the amount of pore space in the soil, as does perlite. Microorganisms, bugs and worms make air spaces, so healthy soil is, by virtue of these beasties, well aerated.

We blend our compost on-site to suit each variety we grow. Each blend aims to optimise drainage, nutrients, aeration and disease resistance. We use (not all at once): peat- free certified organic compost, perlite, vermiculite, sharp sand, coconut fibre, powdered neem cake, lime, mycorrhizal fungi and organic seaweed-based nutrients. Some plants prefer a less nitrogen rich free draining soil, for this recycled polystyrene, fine gravel and/or fine bark is added to the blend.


Biological controls – An introduction

April 13, 2011 § 1 Comment

Biological controls are organisms (insects, nematodes, micro-organisms) introduced to a growing space to feed on pests. Most of these are very small and not interested in humans. Their application is often temperatures specific (so seasonal) and a few can only survive in heated greenhouses.

In the UK we have many species of parasitic wasps, ladybirds, lacewing and hoverflies whose larvae eat butterfly and moth eggs, thrips, leaf hoppers and aphids.


Beneficial predators can be encouraged into your garden by planting members of the apiaceae  family- flowering parsley, fennel, dill and coriander, and also lemon balm, lupins, sunflowers, borage, chamomile, statice, tansies, marigolds, shasta daisies, amaranthus and Queen Anne’s lace.

It is helpful to encourage natural predators to populate your garden by planting crops which will attract them. If local beneficial predator numbers are low, they will benefit from both habitat provision and the introduction of purchased insects to re-populate the locale.


Coming soon to a garden near you ….

April 13, 2011 § 2 Comments

I noticed the first cluster of butterfly eggs on a brassica this morning.

Let the battle begin!

Caterpillars are the larvae of moths and butterflies. They mostly eat anything in the brassica family.

There are three species of caterpillars in the UK- imported caterpillars (green caterpillars with fuzzy skin), cabbage loopers (green with white stripes, arches its back as it walks) and diamond backed moth worms (smooth and green, leaf miner in early larval stage).

Caterpillars do not particularly like red cabbage. A traditional remedy for killing caterpillars is to sprinkle flour on brassica leaves which they ingest and this glues up their insides, or try cayenne pepper, which they dislike. Spraying with neem and insecticidal soap or dusting with pyrethrum is effective. Products containing bacillus thuringiensis will kill caterpillars. Biological controls include the parasitic wasp trichogamma brassicae which targets eggs.

Many gardeners do daily rounds picking off eggs, caterpillars and other pests and killing them, which will usually reduce populations to manageable numbers within a week or two. Physical barriers are the only sure way to keep caterpillars and moths off your veg. Covering with netting or fleece prevents most pest damage to crops.


A very comprehensive guide to beating the bugs

March 15, 2011 § Leave a comment

I found this on an old memory stick, its a 130 page e-book published in 2005 by the Sustainable Agriculture Network (US based) called ‘Manage Insects on your Farm: A Guide to Ecological Strategies’ (click here to read it)

When I say its comprehensive, I do mean comprehensive. I recall reading it in summer 2006 and feeling distinctly smug to be in possession of such a battleplan.

Slugs- They’re coming!

February 21, 2011 § 2 Comments

I give it a month and I reckon the little buggers will be out in force. I have included a few tips on keeping them off your veg (below slug pics) and also some pics of sea slugs, which I do think are very lovely.

Copper wire is a highly effective physical barrier that we use at to keep slugs off the plugs.


Products containing lots of calcium carbonate (lime), especially those with jagged edges (diatomaceous earth), will deter slugs. Organic slug pellets are made from granite or a similar aggregate which is like a cheese grater to a slug’s belly.

Acidic soil conditions encourage slugs so check your soil pH and alkalise the soil surface by sprinkling lime, bone meal or egg shells around plants.

A pond or wetland area will encourage frogs and perhaps newts which feast on slugs. Chickens and ducks will eat slugs and all manner of soil pests. Various types of traps can be made. Trap crops can also be grown. Nematodes are available as a biological control. A skewer and a torch for bouts of mass murder is more therapeutic than it sounds.

And now for the monday morning installment of prettiness! Sea Slugs:

Nutrient deficiency information & photo guide

January 23, 2011 § 2 Comments

Here is a really useful guide I use when identifying nutrient deficiencies in vegetable crops.

I have copied it from our business website, where you can find more of my waffle on growing veg.

This data for nutrient deficiencies are from a paper by Wade Berry at the University of California. The images come courtesy of Dr H Bloom and Dr A Epstein from their 2004 paper entitled Mineral Nutrition of Plants: Principles and Perspectives. Dr Berry’s article can be read at:

This article is part of a huge plant physiology database:




Boron deficiencies are most likely to manifest in large heading brassica. Leaves may appear distorted and cauliflower heads stunted, small and bitter with brown patches on them. Borax and organic matter (rich compost) contain boron.




Calcium is used by plants to make cell walls, for root growth, for nutrient uptake and for pollen formation. Deficiency symptoms include browning leaf tips and margins and always occur on new growth. Leaves may curl downwards. Fruit and flower growth may be stunted and leaves may appear twisted. Cabbages, cauliflowers, peppers, tomatoes and celery are most susceptible to calcium deficiency. Liming prior to planting is advised for all of these crops as lime increases calcium levels in soils and raises pH- a low pH can cause calcium to become locked into soils and unavailable to the plant.



« Read the rest of this entry »

Natural pesticides: Pyrethrum

August 19, 2010 § Leave a comment

Pyrethrum and permethrin are broad range insecticides which control aphids, whitefly, beetles, caterpillars, leaf hoppers and other insects.

We sell pyrethrum plug plants in our online shop.

Pyrethrum is an insecticidal compound which naturally occurs in some chrysanthemum flowers. The variety Tanacetum cinerariifolium can be grown in the home garden and then dried and powdered with care and dusted on plants and on the soil around plants.


Pyrethrum is unstable in sunlight, lasting only about 12 hours, so must be applied daily with great care to avoid inhalation.

Permethrin is a man-made insecticide whose chemistry is based on natural pyrethrum. It was developed to be stable in sunlight for up to 30 days. Permethrin is used in head lice shampoos, flea, tick and mosquito control on dogs and mosquito control on outdoor clothing and camping gear. It is highly toxic to cats, bees, fish and a small number of beneficial insects.

Synergised pyrethrums use the naturally occurring pyrethrum compound but it is bonded to piperonyl butoxide to stabilise it.

Where Am I?

You are currently browsing the Vegetable Garden Pests & Diseases category at The Groblog.