Co-ordinating skills useful with organic gardening

GOOD PLANT: Cleome can help lure bad bugs away from tomatoes and beans.

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Growing a healthy, organic garden requires not just a change in mindset – or fertilisers and pesticides – but a good deal of organisation.

It seems to me that careful planning takes a leading role in green gardening. I've sorted the good bugs from the bad, and devised ways to bring them into the garden or turf them out, but when it comes to weeds it has taken me a little longer to sort them out.

Lush, green and full of weeds – that described the garden at the side of my house a couple of weeks ago. The bare ground was literally open for invasion – and invade they did. I had planned to plant a ground cover there, but after tilling the ground I didn't quite get around to it. A lovely crop of weeds grew in their place instead.

I thought I might get around this by cleverly introducing plants that produce toxic substances that inhibit the growth of certain weeds. It is a process called allelopathy and it refers to the ability of some plants to exude chemicals that can influence the growth of other plants. Those chemicals might be good, as in companion planting, or not so good, as halting germination and plant development. Oats, for example, are said to be good at suppressing the growth of wild mustard, redroot pigweed and barnyard grass. And cucumber plants apparently put a stop to hog millet and white mustard. The trouble is, I don't have any of these weeds. I have dandelion, purslane, chickweed and other common garden varieties. Rye grass is said to hinder purslane, but it is not really the look I am after.

I thought I could try thermal weed control. Flame weeding sounds devilishly dangerous to me, but the man in the shop said I needed only to raise the weeds' temperature rather than burn them to a cinder.

But while weed burners are effective on annual weeds, and those weeds that have not yet become fully established, they're not so effective on established or perennial weeds with deep tap roots – like dandelions, for instance. Weed burners work like hoes – they chop off the weed head, but the roots remain intact.

It's possible, if you keep at it, you could eventually kill them. Think about it like this. Energy is produced by photosynthesising. The plants absorb light energy through their leaves, which is sent down for storage in the roots at the end of the growing season (much like bulbs). If the head of a perennial weed is chopped or "flamed" off, the plant will initiate new top growth by drawing on the energy stored in its roots. If you keep chopping or burning the top off, the plant will eventually use up all its stored energy. With repeat flaming, you should eventually get on top of perennial weeds.

But I'm not too keen on brandishing a fiery weapon in my garden. Had I thought about it sooner, I could have used the fiery ball in the sky. Soil solarisation seems a far safer option. All I needed to do was to place a clear piece of plastic over the tilled area, weight down the edges to seal in the heat, then let the intense heat from the sun kill the weed seeds before they germinated.

However, in the end I resorted to the bottle. I tried Kiwicare's new Organic Weedfree Rapid, a fast-acting, natural weed killer that works within three hours. In fact I could see it working after just one hour. This BioGro certified product uses a combination of pine oils and fatty acids to do the deed. Yet, had I been more organised, I wouldn't have needed to spray at all. A simple mulch would have kept the majority of weeds at bay, or, as originally planned – a ground cover to keep the bare ground from beckoning those weeds.

On the bug front, I'm way more organised. I planted a crop of cleome and phacelia a few weeks ago – the cleome to lure bad bugs away from my tomatoes and beans and the phacelia to lure good bugs to eat bad bugs like aphids.

Cleome spinosa is a long-flowering annual grown as much for its beauty as its novelty. It has long spindly stamens that resemble spiders' legs, hence its common name is spider flower. It's a tall plant to at 1.5m high, so plant it at the back of the border – and keep it away from kids. Its stems have very sharp spines, of which I've felt the sting many a time when picking them for the vase.

Cleome is a great plant to grow as a catch crop because the flowers attract the dastardly green vegetable bug. That might put you off, but better on your cleomes than your veges, I say. In home gardens and small fields, catch crops can be planted around the perimeter of the garden. I visited a reasonably large organic garden where cleome were planted on the borders. The owner said she picked off around 20 green vegetable bugs a day (that she fed to her chooks). She also planted sunflowers as they too attracted the green vegetable bug when they went to seed.

You can plant cleome in large containers if there's no other room. To be doubly effective as a bug trap, insert a stake with a long piece of tubing, painted yellow, attached to the top to lure them in.

Phacelia is a pretty, blue-flowered annual that attracts beneficial bugs like hover flies that eat aphids.

- © Fairfax NZ News

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