Organic Pest Control

Garden Problems

      The sex lives of worms seemed to capture the interest of quite a few people and this has led me to look a bit more closely at the private goings-on of other common garden denizens: top of the list must be slugs. Like worms, slugs are hermaphrodite, meaning that each one has both male and female sexual apparatus. Do-it-yourself however is not on their agenda, and two slugs making out will twine round each other in sexual bliss, exuding slime and  romantically muttering sweet nothings about things like cabbages and sprouts. In the case of the great grey slugs, this can go on for two hours before, in a fervour of excitement they consummate the act, hanging on the end of a length of slime suspended  from a handy shrub: a sort of slug equivalent of position 98 minus the wardrobe. They then both go away, smiling beatifically, and lay a cluster of little pearl-like eggs.

      Now, while all this is perfectly true and explains the frightening proliferation of slugs, it has little to do with the subject of this blog. It did get you reading though, didn't it?

Slug on the prowl

      A lady called Beth contacted me to ask whether I could suggest non-chemical pest controls in the garden, as she is trying to grow vegetables organically. A few things spring immediately to mind: nettles, soaked in water for a couple of weeks, yield an effective, though smelly, mixture good for controlling aphids (greenfly and blackfly), at the same time as acting as a fertiliser; rhubarb leaves (boil 3lbs for half an hour in 6 pints of water with a few soap flakes to aid adherence), provide another useful aphid control - then use the stems to control constipation; the dried, powdered leaves of rue (Ruta graveolens), spread on seedbeds, are said to deter birds and other seed eaters and rubbed through the coats of dogs and cats will get rid of fleas; even the ubiquitous marestail can be used as a tea to protect against blackspot and mildew, while soft soap is used to kill brassica whitefly and cabbage white butterflies. Apparently it acts as an enema so I suppose, like Elvis, they die on the toilet.

      This brings me back to slugs, as they must top everyones' pest list: while pellets containing metaldehyde are effective, there are ongoing concerns about the outcome when natural predators like hedgehogs and birds eat the corpses. On the other hand, slugs drowned in a beer trap (a) die happy - their eyes are still going round the following day - and (b) their corpses do no harm when placed on the bird table, although a blackbird may occasionally fly into a lamp-post. However, Gardening From Which worked out, some years ago, that, to completely eliminate slugs, you need a beer trap every couple of square feet. This means that, unless you have shares in a brewery, it's going to be a pretty expensive project. You should also know that slugs in posh areas prefer gin and it, while milk is popular in the American bible belt.

Slug Eggs

      Nematodes provide an effective alternative to beer: these are microscopic eel worms provided in a pack containing enough to protect a forty square metre plot for about six weeks. They are watered on. Unfortunately the effect on snails is not quite as good, because these slugs-with-caravans tend to move from plant to plant above ground, rather than making contact with the soil. Copper bands, available in garden centres and wrapped tightly round pots, cause an electric current to be created through contact with a slug's slime, resulting in them getting a shock and falling off . This doesn't actually kill them, but it certainly removes Hostas in pots from the menu. A couple of copper wires, used in the same way, can be equally effective. Additionally, a tea made from Artemisia and watered on is also claimed to deter slugs and snails, although I haven't actually tried this one.

Slug pub with inebriated customers

      The more I write on this subject, the more information comes to mind (thanks for the question, Beth), so more blogs will be devoted to garden problems and how to control them. I can even see the sex life of the aphid looming on the horizon.

      Calm down. You'll have to wait.

Lawn Problems

 The Trouble With Grass

       Two questions which keep occurring to me are: 'why do footballers constantly spit?' and 'why don't they hurt themselves when they slide on their knees in saluting their own brilliance after scoring?' These conundrums have bothered some of the best minds for years without a satisfactory answer -even Einstein gave up and turned towards simpler matters like relativity. Likewise I've spent many hours pondering until, in a flash of blinding inspiration, it came to me. There is only one answer to both questions: they spit so that when they slide on their knees they are cushioned on a protective sea of goz. Proof of this can be seen in the fact that teams on a good run spit more than the ones destined for the drop: the greater the likelihood of scoring, the more protection is needed. Come to think of it, Einstein could probably come up with a pretty good equation for that.

Organic lawn-mower (Picture courtesy of daughter who runs a national archive of sheep pictures)

     
      No-one seems to pay much consideration to the grass though. The general perception is that grass is grass and you can do anything to it and it will still bounce back. This is only true to a point. Grass is the same as most of the things in the garden in that it is a plant. Unlike most plants though, it will tolerate being cut down regularly, walked on and footballed on to quite an amazing degree. The gardening experts on TV will blithely advise scarification, aeration and top dressing on an annual basis to remove a build up of detritus on the surface, allow air to the roots and  improve growing conditions. This is fine for the experts paid by the TV companies.They  wave a rake around to the camera then retire to their mansions, clean their carefully dirtied hands and leave gardeners to do the proper work. However this can be a big job, especially if you've got a sizable lawn and are working, so it sometimes suffices to simply treat the areas most used: the route to the washing line, shed  and so on - the rest will usually look after itself with only the occasional blitz.


A half-decent lawn is an effective foil to the beds

      Thatch - a surface build up of dead grass, moss, leaves and other detritus - can lead to water being held near the surface. This, in turn, result in grass roots  growing shallowly  in order to exploit it and when a drought (remember droughts?) comes along, there are no deep roots to reach water reserves lower in the soil. Removal of thatch can be achieved by dragging a spring tine rake through it, but use of an electric scarifier makes the job a lot easier and does away with the days in bed recovering.

      One of the main causes of lawn problems is the gardener's wish for a bowling green sward, leading to the grass being cut to about a quarter of an inch. This doesn't take into account the fact that bowling greens have been created using certain varieties of grass, mainly bents and fescues, which react happily to being close-shaved. However, most lawns consist of other grasses which suffer if cut lower than an inch. Ignoring this leads to poor growth and the inability to compete with moss and weeds. Walking on frozen lawns can cause brown, footprint shaped, marks in the grass, because the weight causes the grass stalks to break off at the base. It will probably recover, but is a classic example of the dangers of cutting to closely.

      But coming back to footballers: why do they pull their shirts over their faces when sliding around after scoring? Is it to show off their tattoos or hide the agony when their knees hit a patch the goz missed? Answers on a postcard, please.

Gunnera manicata (giant Brazilian rhubarb)

Gunnera manicata

Graham has written (see comments - Lichen, moss and liverwort) and asked about whether it is really necessary to cover the roots of Gunnera manicata with bracken when the foliage dies back in autumn. He also asked for my thoughts as to whether the species tinctoria is a better choice, because it is hardier, having become a pest species in Ireland.

Gunnera manicata at Fletcher Moss Gardens

Gunnera manicata is sometimes referred to as the giant Brazilian rhubarb, because it comes from Brazil and has big leaves like rhubarb. However, it isn't edible and can grow to over six feet, ideally next to water. Interestingly, it has developed a relationship with a nitrogen-fixing bacteria in much the same way as members of the pea family, and this makes it easier for it to survive in nutrient poor soils. The closely related G. tinctoria comes from Chile and differs in that the stalks are edible, being used as a vegetable or eaten raw when the stems are peeled.

My experience of growing G.manicata was at Fletcher Moss Gardens, where we religiously covered the roots, in the traditional way, with the old leaves, pegging them down to prevent disturbance. When we had a series of mild winters the thought was that maybe we could get away without carrying this out, but thankfully we persevered because we were then hit with some humdingers which would almost definitely have wiped the plant out. In view of the fact that Graham lives in the hills above Cockermouth - a hardier environment than the South Manchester Riviera - I would say the plants should certainly be protected in this way or, as he suggested, with a thick layer of bracken.

The R.H.S. classify G.tinctoria as being even less hardy than manicata, so I would suggest that it also will need protection. The climate in Achill Island and County Mayo in Ireland, where it is invasive, is probably considerably milder than the badlands of Cockermouth, explaining its rampaging nature there.

Thank you for commenting, Graham - all questions are welcome.

Lichen, moss and liverwort

Interesting Problems

      I once took my three children on holiday in Dumfriesshire. We were staying in a cottage about five miles into the hills from Dalbeattie. The idea was to have a week away from radio and television (computers didn’t loom large then) and spend time playing games, reading and actually talking to each other. My wife had booked the place but couldn’t come because she had to work. She said.

      It was ideal. The fact that water was hand-pumped from a bog at the bottom of a field led to some interesting wildlife studies over a cup of tea, and the creativity involved in advertising ‘Hot Shower’ as one of the amenities made the invention of television pale by comparison: the shower consisted of a Killaspray, which is a five litre plastic container with a pump handle and a length of hose attached to a spray nozzle. It is intended for killing pests. On this one, the nozzle had been replaced by a watering can rose. The idea was that you heated water on the Calor gas stove (there was no electricity), poured it into the container and held the watering can rose over your head, sweating as you pumped like hell. Water then trickled out at the rate of a two-year-old urinating, with the perplexing result that you were more in need of a shower after than you were before.

Lichen covered tree

 

      And in these sort of conditions we existed for a week. Perhaps more features of this holiday, which became annual, will be shared in future blogs but the point I want to make is that life forms can exist together under the most intimate and hardy of circumstances. Take lichens, for example. These can be seen in different forms growing on trees and rocks. Looking like a single plant, they actually consist of an alga, which has chlorophyll and can make its own energy-giving sugars, and a fungus, which is unable to do this. The fungus is, however, more able to take in and store water and mineral nutrients. These cohabitors then share the fruits of their labours so successfully that some species can live for hundreds of years.

Yellow lichen

 

 

      A question I’m often given is ‘is this stuff killing my tree?’, and the answer is no. In fact the presence of lichen indicates the clean atmosphere it needs to operate in, implying a healthy environment. Lichens don’t live happily with pollution and scientists use them as one pointer to the health of the atmosphere.

      Liverworts are sometimes mistaken for lichens, but  are structurally closer to mosses. Like mosses, they thrive in damp conditions and can be a problem where the gardener is an over-enthusiastic waterer.

Liverwort

 

      Another common question is ‘how do I get rid of moss in the borders?’ People resort to applying chemicals which kill it, only to find it rearing its head again fairly quickly, simply because they persist in leaving bare soil between their plants. Bare earth is like your loft: leave a space and it’ll get filled with something – not old Christmas decorations in this case, but moss or weeds. The simple answer therefore is to copy nature by planting to cover the soil. The same in the lawn – get the grass growing healthily and it will out-compete moss.

Moss growing on fence post.

 

      The second most useful piece of information I can give is to work as closely to nature as possible in the garden. The first is to hire a cottage with a proper shower.

Any questions about any of the above or other aspects of gardening? Put them under ‘comments’.

 

 

 

 

 

 

Composting Part 2 - Worms

Composting Part 2

When I was nine or ten, my mate Dave, from five doors down, had a pet grass snake called Harris. We’d heard about snake charmers in India and decided to have a go ourselves. In the absence of a cobra or Indian flute, it didn’t seem a far stretch of the imagination to substitute Harris for the snake and a recorder, ‘borrowed’ from school, for the flute. Harris did’nt rise and sway in his glass-fronted tank but he did actually raise his head a bit when the music started. We thought this was due to the hypnotic beauty of Dave’s rendition of ‘Pub With No Beer’ but, in retrospect, was more likely a result of the pain rendered on his musical appreciation. Snakes ‘hear’ by detecting vibrations and these particular vibrations didn’t exactly gel with the ones the Beach Boys sang about.

Anyway, this was when I got interested in worms. I couldn’t afford a snake and thought a big worm would be just as good. It wasn’t, but at other things it excelled:

Charles Darwin, in one of his books, stated ‘It may be doubted whether there are any other animals which have played such an important part on the history of the world as these lowly organised creatures’. My first thought was of dinosaurs, but he was referring to earthworms.

Young worm pointing at developing clitellum with his tail

 

Worms burrow, taking  soil in at the mouth end. They then pass it through the gut, which extracts a bit of nutrient for breakfast, and excrete the remains higher up in the ground. Hence, worm casts. Darwin reckoned they lift 10tons of soil per annum in an acre of average English meadow, and the outcome is important to plant growth: burrowing creates tunnels which enable soil drainage and aeration. Soil they deposit higher up contains plant butties in the form of minerals which have been washed beyond the reach of roots, so that they are once again available.  The fact that worms then line the tunnels with dead leaves further illustrates their importance as part of nature’s recycling system, returning to the earth what came from it.

Of the 25 different species of earthworm in Britain, it is the tiger worm, or brandling, which we use in wormeries. This is the one commonly found under damp cardboard left out for the binmen. It works on the surface and is one of the most important compost makers.

Worms are hermaphrodite, which means they have both male and female sexual apparatus, implying that they could fertilize themselves. However, it is understandably more fun to do it with another worm, so you will find them lying together and exchanging sperm which is stored in special body sacs near the head. If you witness this, creep close and listen carefully. With a bit of luck you’ll hear them whispering  things like ‘ooooh, do it again!’. Each worm will then go away and lay eggs into a ring around its body called the clitellum. When ready, it’ll wriggle backwards out of the ring so that the sperm sac fertilizes the eggs, which are then deposited in a cocoon in the soil.

We tend to think of worms as being a few inches long. However, the biggest earthworm, the Gippsland Giant, found in Tasmania, can be as long as 10ft so, cut into sections, could support about 8 fishing trips. On the negative side, a worm cast it made in your lawn could cut out light in the kitchen.

At one point I was under the impression that worms are brilliant mimics. The one I kept as a pet, he was called Bert, could do being a rusty nail to perfection. I thought this was his crafty method of escaping detection. However, turns out it wasn’t. He’d been dead for a fortnight.

If anyone would like more information about worms (or other things pertaining to the garden), let me know in the ‘comments’ tag.