This may sound a little eccentric but ….

Just now the border surrounding the asparagus bed is looking as if it might take over – it certainly needs a dramatic thinning, but there is some method in the madness because we need to harvest a lot of calendula flowers to make cream, and calendula is also reputed to deter asparagus beetle. Allotments are peculiar places inasmuch as they can be plagued by pests that spread through the site from one plot to another. If every plot holder controlled their pests, preferably organically, they’d be less invasive. On our plot we’ve been overwhelmed this year with blackfly, which got going several weeks before the ladybirds(ladybugs) bred fast enough to limit their numbers. So we picked out the broad bean growing tips and harvested ladybirds wherever we found them so we could relocate them on an instant banquet. I’ve no idea whether it worked but eventually the blackfly were diminished and we’ve just finished harvesting a reasonable crop. What with the awful spring weather it felt like we were snatching victory from the jaws of defeat, but a few of the neighbours simply uprooted their beans and composted them. We’ve had allium leaf miner destroy our leeks for three consecutive years – it’s rife across the site – and so this year we’ve grown all the alliums – garlic, onions and leeks – under fine insect mesh in an attempt to keep the bugs out. We’ve also netted the carrot family in the same way; it doesn’t look so nice but if it protects the crops without any chemicals then it’s a good idea.

Asparagus beetle is another one. For three years – as soon as we allowed the fern to grow at the end of the season – the beetles moved in. Dozens of voracious little grubs would chomp their way through the fern, weakening some of the plants enough to kill them. It became a daily task to sort slowly through the bed, squashing every grub we could find between thumb and finger. We found it was the most effective deterrent, but each day there would be a new hatch and so it was hard work. We sprayed once or twice with organic pyrethrum, but it can only be done under perfect conditions early in the morning because it’s a broad spectrum insecticide and could kill friends as easily as foes. It’s also very expensive and so we kept on with the daily slaughter by hand.

This year we thought we’d try growing a border of calendula around the bed to repel beetles and it seems to be working. Madame has only picked off half a dozen grubs this week, and the fronds are looking sound – capable of feeding the roots for next year. However the vigorous marigolds are shading the asparagus plants nearer the edges so we need to take the flowers for drying and then thin the border dramatically. So far it’s one up for the companion planting.

I wanted also to mention a new (another one!) book which would be of more interest to UK and Northern European gardeners because it’s about garden wildlife. Titled “Guide to Garden Wildlife” it’s illustrated beautifully by Richard Lewington with the birds illustrated by his brother Ian. This season’s foray into deliberate wildlife gardening has forced us to pay a lot more attention to what’s flying around, wandering and crawling around, swimming around and tunnelling underneath the allotment. A single, portable, illustrated field guide ticks an awful lot of boxes since we are now so often confronted with an insect whose name we don’t know. Wildlife gardening removes the convenient (and deadly) division of living things into crops and enemies. The netting and companion planting that we’re experimenting with all flow from the desire to combine the protection of our crops with increasing the diversity and health of the birds and insects on the plot.

Here’s a typical decision we’ve had to make. Until we put in a pond I’d never heard of iris sawfly, but they’ve moved in with a vengeance – fat and juicy little grubs chewing off the leaves. For us they’re a nuisance – more of a cosmetic nuisance it has to be said; but for a hungry bird, or for one of the many other insect predators it’s a meal. So we put up with the knackered leaves and hope that the dragonflies, water boatmen and many other creatures enjoy a meal at the expense of a little patience on our part. Once we’ve accepted that we’re just another predator in the great wheel of nature, then the way we garden becomes a profoundly moral issue. We take what we need, discourage dangerous pests as far as we can and let the rest thrive.

The book has enthused me enough to try to identify more of the species of bee and fly that look rather like one another. Hoverflies, for instance, are a big group with very different lifestyles and we want to move beyond bumble bees and butterflies. Even moths, I wonder recklessly, could be worth a go. It would be pure pleasure of course but more than that I’d urge you to get hold of a copy and read Ken Thompson’s marvellous introduction. His take on wildlife gardening is pretty radical because he refuses to get drawn into a sterile argument about what’s wild and what’s not. Words like wild and natural muddy the waters to no useful end. The sad fact is that gardens are a tremendous, and sometimes the only species rich environments left in a highly populated country, practising industrial farming and building more and more concrete infrastructure. If any moronic cash strapped local council wants to turn an allotment into a car park or (another) profitable housing development for the elderly wealthy, and believe me they often do, then it will be essential to have to hand detailed records of the allotment’s natural history and biodiversity.

We’ve had a trail cam for ages, but we’ve never dared deploy it on the allotment for fear of it being stolen or vandalised – sadly it’s a problem for almost all allotmenteers. But now we’ve got a purpose built padlocked steel box which should stop almost anything except a pre-prepared theft using tools. We’ve known about the wildlife that we share the plot with through seeing what they do. Badgers, for instance, have an amazing capacity for judging the sweetness of sweetcorn and unless you protect it, it will be stolen the day before you were going to pick it. There are rumours of small deer and of course we see the rats and the flying nuisances, mostly pigeons. Mostly though, we see the tracks and the sign but not the animals themselves. But now we’ve captured some lovely video of a fox sitting and cleaning itself right in front of the camera; a curious magpie almost tapping the box (it must have glistened) and a great sequence of a fat rat, nose twitching searching for our broad beans. Rats love the beans and occasionally we find a whole pile of empty pods. This one, however, was out of luck and it jumped over the boards into a cleared bed.

However, watching 30 seconds of video for a short glimpse of a fox is pretty boring and so I’m trying to teach myself video editing so that I can publish the best bits here. I may be some time!

Measuring the marigolds

Miracle cures abound in the organic gardening world, and the marigold is a top tip for all sorts of duties. However, it’s a bit more complicated than the stories usually suggest and like most people we’ve bought a packet of marigolds at the garden centre and discovered too late that they weren’t the ones we should have bought. So here’s a very quick disambiguation of the minefield.

  • Two kinds of Marigold share a common English name, and even look similar but they belong to two separate ‘tribes’, so let’s look first at the Pot Marigold, Calendula officinalis* which has a country cousin called – unsurprisingly the Field Marigold – Calendula arvensis which is rather uncommon so we needn’t worry too much about it. The Pot Marigold is a lovely plant; easy to grow and it’s a good pollinator attractor. It self-seeds freely so it’s best to harvest the flower heads before they mature unless you want to save the seeds. It’s also the source of the flowers from which calendula cream is made – it’s got to be one of the safest and easiest home medicines to make and it really works. The picture at the top is a part of last year’s crop of flowers that we turned into a wonderfully fragrant ointment last autumn by steeping the flowers in sweet almond oil and then adding beeswax to form a firm cream. It’s great for skin problems – although the price of organic almond oil will make your eyes water – but even using the best ingredients it’s half the price of the commercial product.

The other ‘tribe’ of marigolds are the Tagetes; and these are the ones whose roots are said to exude a chemical that deters or even kills some of the nematodes that can cause problems in the garden. There are three members of the family you’re likely to meet in the UK (the US has at least one additional member that I know nothing at all about).

The first of the three is Tagetes erecta which is very confusingly known as the African Marigold in the UK in spite of originating (as they all do) in South America.

The second is Tagetes patula – the French Marigold – which is a smaller plant and is the one that’s most often interplanted for its suppose effects as a pest deterrent. We use these all the time because, being quite small they’re easy to run in between tomatoes and other crops. As to its effectiveness it’s hard to say, but they’re very pretty and if they deter pests then all the better.

The third is Tagetes minuta the Southern Marigold which – again confusingly – is actually taller than the other two. The minuta in the name refers to its very small flowers. This one hardly appears in the seed catalogues because it’s not much of a looker, but ironically it may be the most potent of the three, because aside from its capacity to see the nematodes off it’s also said to be capable of getting rid of some of the most pernicious weeds like couch grass and bindweed. Anything that can achieve such a miracle is worthy of a mention but apart from a paper published by the HDRA I haven’t found much evidence. It has certainly been widely used in South America as a herbal medicine. My only caveat would be that if it does possess the magical powers that are attributed to it, it might be a very poor companion plant if its secretions attack the very plants you’re trying to grow. However I’m sufficiently interested to try to grow a small patch so I can try out its insecticidal effects against the asparagus beetle that regularly attacks our asparagus bed. This time last year we were cutting our first spears, but after such a cold and wet winter and early spring there was no sign of any spears today when we peeped under the fleece.

So I hope that’s of some interest. This is a short piece because we’re so frantically busy on the allotment. The polytunnel is already showing us new possibilities. Some containers of very early potatoes have needed earthing up twice in the last week, and our seedlings just love the warmth and light- although we’re still covering them at night. Happy days!

  • * Having posted this piece yesterday I was reading John Jeavons’ marvellous book “How to grow more vegetables ..” which I’ve only just been able to get a hard (ie real) copy of, and he unequivocally lists the pot marigold Calendula officinalis as a companion plant to tomatoes.