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.


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