What is this? Taken 28 May 2010
Five weeks later - on 4 July 2010
What is this? Taken 28 May 2010
Five weeks later - on 4 July 2010
Why an experimental veg patch?
First of all, it’s experimental for me. I’d never tried growing vegetables and soft fruit in raised beds before, and I’ve not seen anyone trying to do this locally on a large scale. The “literature” (especially information on the web) certainly says you can: you can find pictures of rows and rows of raised beds; and professional growers do this all the time. One just has to think of acres of strawberries under glass, often hydroponically and on raised “beds”, making picking and maintenance so much easier. And others have created a whole culture out of “high density” cultivation (e.g. see here). But not using my soil, my climate, and my energy limits! So I’m trying it for myself.
In my locality, gardens are big compared with England, and it’s not unusual, if you live in the country, to have a potager some 500 m2. There are traditions stretching back generations regarding how to manage these. When France was largely rural this was the responsibility of the women folk, whilst the men tended the livestock and worked the fields. And the tradition of the large potager persist, and nobody seems to try growing enough vegetables to feed a family using raised beds.
Two generations of leeks!
My reasons for developing raised beds, though, are mainly to do with the configuration of the sloping terrain at Valanec, the very poor quality of the soil, and a desire to avoid digging and heavy weeding, bending, lifting and scrambling about in the mud. And those who visit the garden, or see it from the nearby lane, have expressed encouragement, and I have concluded that traditions are changing. There are more houses with smaller gardens, and families (including young children, the old and infirm) want to have a try at producing vegetables free from artificial (chemical) fertilizers and pesticides. Raised beds would suit them very well.
This brings me to the crux of the “experiment”. The key question is: how do you manage intensive cultivation, in raised beds, without using any artificial or non-biological resources, and how efficient is it?
For those who read French, the methods of construction are described on the Hanvec 21 web site (here).
The First Two Years
Having started with one bed using recycled materials (in the summer of 2009), I saw such immediate benefits that I simply kept going. I improved on the original construction and ended up with 7 raised beds, plus two larger level areas for plants that like a lot of space (potatoes) or tend to roam about (courgettes, squash and others in that family).
At the end of 2010 I decided to abandon the large potato bed. First, it produced too many potatoes. Second, I’d have had to rotate the potato crop somewhere : but where? And third, I needed to make an asparagus bed, and this ties up a patch of ground for ten years or more.
Plans for 2011
The plan for 2011, therefore, is to follow up on an idea described below for intensive potato growing. I plan to use one raised bed for early potatoes, and reuse it for other crops from the end of June. Another bed will house a later “main” crop, for conservation. And in a third – or part of a third – I’ll try and grow some big potatoes for baking in their jackets. And since each bed is only about 4 m², I plan to play with the levels of the earth so as to encourage the plants to produce more tubers at different levels. Rather like a giant potato barrel. It means digging out 20 cm of earth before planting, and setting this to one side, but the soil is now so friable and pleasant to use that the task seems manageable.
The only problem with this is that potato haulms can, as we all know, be voluminous. Maybe I need to identify varities with naturally stunted foliage!
The asparagus bed prepared in October has, by January, almost absorbed its generous coating of mulch, and the birds have a had a great time in the cold weather hunting for worms. Another bed contains gigantic broccoli, and the florets are just beginning to form (mid January) and should crop in March. Another portion of the old potato bed contains winter spinach, and that has not proven too successful. The slugs adore the spinach, and I shall need to grow spinach in one of the high beds in order to foil these predators.
Result
The net result of this “experiment” is that the original 200m2 area designated for vegetables has been re-modelled to provide about 70m2 of intensively cultivated surface.
The system raises questions. In fact, all visitors to the potager ask questions. I have answers to some, but not all – hence calling it experimental. Some questions are obvious – like is it worth the trouble? – and I can begin to answer those. But other questions raise issues in agronomy I am hardly in a position to answer. Below I list some of the more tricky questions I want to answer. Maybe those who read this can make suggestions.
Questions to answer
- Density What are the limits to intense cultivation? In 2009 I found that one could get good results for beetroot, for example, planted twice as densely as recommended. Growth was maybe slower, but the end result was excellent. But what are the limits or side-effects of dense planting (on, say, vegetable size and health)? I want to check out what others have discovered on high-density planting, the trade-off between space and fertilisation, and the maximum sequence of different crops on the same bed.
- Mulching How to manage the autumn/winter mulching? Maybe temporary boarding around the beds will help retain the grass cuttings/leaves/compost mulch I plan to use. Would it be best to try and shred/chip the mulch before applying it? The mulch on the onion bed this summer was too dry and uneven for my liking.
- Carrots Do raised beds effectively prevent carrot fly? [Answer is yes, almost: but I'll plant the carrots with the garlic in 2011.]
- Fertility Will the soil in the beds stabilize naturally? The potato bed (earlies) has produced over-abundant foliage, and I wonder whether this is because of imbalanced natural fertilizer. When you make the bed you naturally put compost in the bottom before infilling with soil/sieved soil. I plan to use Bocking 14 comfrey as a fruiting/flowering stimulant and wonder whether it might not also promote excessive growth. I have also started to use a few handfuls of dolomite in order to counter-balance the natural acidity of the soil here.
- Watering The beds seem to retain their humidity very well. However, during very hot spells one has to water them (most days). The watering is highly localized (it only goes where you want it to – not like sprinkling). But would it not be better to have a drip feed (goutte à goutte) system from rainwater – which could be collected from the greenhouse roof? Better for the strawberry bed, no doubt.
- Rotation How important will plant rotation between the beds prove? This is directly related to density, of course. [But, contrary to good practice I planted leeks after the shallots in August 2010, and they are doing very well.]
- Weeding The beds with least weeds are those where I sowed onto a commercial compost bed (about 4cm deep – see parsnip picture below). Those with most weeds (see carrot/radish picture below) are where I sowed onto finely sieved earth (carrots and turnips). But how well will the compost become incorporated into the soil?
- Pests What “hidden” problems may arise – e.g. disease/viruses affecting a bed? First impressions are that I suffer far less attack from slugs and snails – maybe they don’t like crawling 60cm vertically and then trying to move across mulch. I also plan to use insect-proof netting for crops like Broccoli which prove such a magnet to the cabbage white butterfly.
Raised bed with parsnips – and no weeds…
Radishes (& some carrots) & lots of weeds
Progress
As things develop I’ll insert photos in chronological order, and which will, I hope, say it all …
4 July 2010: the onions on the right, planted (from sets) directly into ground covered with a light compost mulch, have done less well than those protected by black plastic. This year I’ve had a bumper crop of shallots, also sown under black plastic. The extra warmth and moisture retention have obviously proven critical.
These onions were planted on 28 March; others in a raised bed had “germinated” by 15 April, but those pictured here took until 7 May to get going. There followed an extremely cold spell. By 4 July one can see the difference.
Rhubarb A five-year old rhubarb plant was moved into the potager in the autumn. I split it into five pieces. According to various sources you can’t expect much growth in the first year from the “new” plants.
However, they obviously like their new home: end June we had an excellent crop of stalks. Since the new plants had not established themselves very well I took the proportion of holding them in the ground firmly when pulling the large stalks. A week later (photo) they are all doing very well.
One of our visitors at the open day pointed out that you can cultivate rhubarb with much more rosy stems, and which is sweeter than ours. Something to investigate.
Potatoes Started lifting my “main crop” potatoes on 6 July. This is very early, but I planted early (almost 100 days ago), which is about right for Charlottes, and some tubers are a nice size.
Five minutes work
The haulms had been collapsing a little (especially the Mona Lisas), and yellowing, and there is occasional evidence of blight on the odd leaf. My main reason for planting so early was indeed to be able to harvest early, before the main blight season in July-August. I cut off the haulms of some plants almost a week ago as a precautionary measure.
Above all, though, I wanted to liberate the space for pricking out additional endives, and later the broccoli and maybe extra leeks; otherwise, I could have burnt the haulms with acid and left them in the ground until the end of July as the local farmers do. Following advice from my neighbour Raymond, however, I’ve left half the crop in the ground with the haulms removed, since he says they will not keep in storage unless the skins have thickened. 3 weeks in the ground should suffice.
Potatoes being lifted, showing surface mulch
The crop is vastly improved on 2009, but I’ve noticed things that make me think I could improve further. One high density gardener reports that he doesn’t grow potatoes because they “take up too much space”. I think the trick may be to try and get better yields from less seed. My earlies, the Chéries, planted densely in a raised bed, did better than the main crop because the soil was lighter, more nourishing and more moisture retentive. Indeed, you could virtually harvest them with your fingers. Instead of earthing them up I had applied an extra layer (about 10cm or less) of my home-made composting mix (sieved soil with some composted material). As a result I had virtually no exposed tubers. This is in contrast to the main crop where some of the surface mulch blew away, and the soil proved a bit drier (though not catastrophically so – indeed the lack of rain since April is so severe that the earth would have dried out much more than it did, were it not for the composted material worked in last autumn and the over-winter mulch).
Considering that a well-known technique for dense potato yields is to grow them “vertically” in bins, and given that many earlies produced commercially are clearly grown not in heavy soil but in compost mixes, or even in sand (as on the Ile de Batz near Roscoff), I have wondered whether I could not halve my surface area whilst doubling my yield. A raised bed could have about 30cm of the top soil removed at planting in early March, and set on one side. Then, as the potatoes develop, the soil would be replaced. This would encourage the plant to put out new tubers as the level of the soil rises. This would also facilitate my use of the protective fleece (against frost etc.), which would not touch the top of the haulms so soon. I noticed this year that the contact of the wet fleece tended to damage the leaves.
The approach would halve the cost of seed potatoes, free up valuable surface for other crops like peas and beetroot and onion, where space has been restricted this year, and avoid loss through tuber greening. But it involves more storage, and therefore less time over winter in which to consume the crop.
Courgettes Spectacular this year.
4 happy courgettes
After a difficult start (all ten seeds sown on 15 April were eaten by a mouse overnight in the greenhouse) I got another batch to germinate and pricked out four robust plants on 15 May. The variety is Tarino (F1) and fairly resistant to viruses, though the main leaves will no doubt attract odium in due course. Currently they are producing 3-4 courgettes a day between them.
A well-known problem with courgettes is that if you forget to pick them in time they become gigantic, almost over night. Discussing this with a keen gardner the other day I was told to let them reach maximum size, pick them just before they show signs of turning yellow, and you can keep them in a cool dark place for months. If anything the taste improves. Having tried this I have to report that all was well until Xmas. However, at this point some of the massive courgettes started to rot (although stored in an unheated garage during a very cold winter period). It suggests that, for keeping cucurbitaceae it is best to rely on pumpkins and squash and finish off the courgettes before Xmas.
