Bed preparation and planting of raspberries

In December we had a delivery of bare root raspberry canes destined for the new fruit cage. The loss of our old fruit cage during the renovations of the kitchen garden was a bit of a blow as it was so productive and had such a large area for growing all sorts of soft fruit as well as fan trained cherries and other trees. The site for the new fruit cage could not be less promising. Part of it was a small area of effectively wasteland, a dumping ground for stones, rubble, and other detritus, and the rest was under a concrete slab. The slab had to be cut back to make space for the old polytunnel frame, which is now being used as the basis of the fruit cage and will eventually sport some new netting. The soil beneath was just about the worst in the garden; so compact that it could not be worked with fork or spade, lacking in organic matter where it had not been cultivated or had anything much growing there for years. Even the toughest of weeds struggled to do anything here.

Even the worst prospect, however, can be transformed into a suitable growing space if appropriate materials and effort are applied. In this case that meant hacking out the rock hard soil with a grub axe to a depth of one foot or so, then breaking up the base until a fork could finally get in there to loosen everything nicely. Copious amounts of horse manure were added to the bottom of the trench and the soil sieved back. This is quite a labour intensive task, for which we recruited a couple of younger and fitter specimens than we. A large sieve built out of scrap timber and old wire fence mesh helped immensely. It is surprising how quickly it can be done with two people working at it – one shovelling soil into the sieve and the other giving it a good rummage. Of course, the objective was not to remove all of the small stones, just the larger material, so the mesh was coarse and the soil went quite readily through the sieve. The sieve was put together on a whim, though one point was considered – sizing it to fit nicely over the top of a wheelbarrow – and this turned out to be quite handy.

The sieve, a smaller version of the design used when we originally sieved some of the vegetable beds. The course mesh only removes excessively large stones.
We must have removed at least 500kg of stones from the raspberry and strawberry beds. Other parts of the fruit cage were loosened up and manured but not sieved.
Small stones are fine, but these are not the sort of thing one wants in a cultivated bed.

With the soil back in the bed, more horse manure was first spread on top and then forked into the top layer of soil where it has all but disappeared, no doubt thanks for the efforts of earthworms and other soil goodies. A thick layer of composted green waste was spread on top, some of which remains, though plenty appears to have been worked in. This demonstrates, really, the beauty of a no-dig approach. Although we obviously had to break up this soil – there is simply no way in which a layer of compost on the surface would have much effect on the compacted ground below – the material spread on top of the now improved soil will not have to be worked in and in future we can simply mulch the bed with compost or manure and leave it to nature to deal with.

We are in a location that is surrounded by old gravel extraction sites, which are now attractive lakes. The soil in places reminds me of a self binding aggregate, the sort of thing historically used for garden paths, such as that known as hoggin. These materials contain a mixture of particle sizes, from stones to fines, such that when laid and compressed they bind together, without the aid of a chemical binder such as cement, into a fairly solid material – solid enough to form a hard wearing surface. Our soil does something similar, and in areas that have not been cultivated it can present an impenetrable barrier to roots and, presumably, soil life.

It is not just a question of the quantity of larger stones, though that is also problematic, it is the degree of true compaction that naturally occurs; true compaction, that is, in contrast to merely firm soil in which roots can happily develop. Whilst excavating a border in one of the greenhouses I was amazed to find a wall of what I first assumed to be a lump of old concrete but later realised was just the compacted soil beneath the path. There had been no discernible interaction between the soil in the border and that beneath the path. Naturally the latter is not watered but even so some grey area between the two might have been expected, with a more gradual change from cultivated and healthy soil to uncultivated and lifeless, but this was like a wall of rock or concrete – too hard for a hand trowel to have much of an impact.

We have also observed the effects of compaction with numerous trees, even when mulched with organic matter. Some poorly specimens were removed years ago to clear the space for the kitchen garden and we found that their roots had either run along the surface of the ground, just below the grass and failed to get any deeper, or had swirled around in their planting hole and become ever more bound up, just as might happen with a pot bound plant. In no case had the roots developed in the normal fashion.

We later discovered to our great disappointment the need for either a much more robust root stock or some rather more serious preparation – no doubt requiring a digger – for our orchard trees, few of which have developed as they ought. Advocates of the no-dig approach – with whom I would, in general, find much with which to agree – suggest preparing a new bed merely by laying down organic matter on the surface. I would certainly agree that this can be done in many cases. There are times, though, when more substantial effort is required at the very beginning of the process, especially if hoping to transform a piece of land in a reasonable period of time. The area of our fruit cage did have a pile of manure sat on it once upon a time, to no obvious effect. I doubt whether a no-dig approach could really improve matters here except possibly over a long time frame. When a fork cannot penetrate the ground and it needs to be hacked out with a grub axe, I think it is beyond the scope of a mere mulch.

We could, though, have built raised beds. We have edged the beds with six inch gravel boards as usual, which was needed to contain the amount of organic matter we added, though the level has since dropped considerably. I did not want extra height here in the fruit cage, however, and a lot of top soil and compost would be needed to fill the beds. We opted, therefore, to work on the existing ground and if we have succeeded in permanently breaking up the compaction – which I hope that we may have done with the addition of so much organic matter – then the situation should be ideal. The soil in our vegetable beds was also poor when we started, but now, after years of mulching with composts and manures, they are rather pleasant to work if still somewhat sandy. The ground used for the fruit cage was considerably worse, however, which explains how it had remained uncultivated despite being in the middle of the kitchen garden.

After the effort of preparing the bed, planting out the raspberries was a simple matter. They are generally shallow rooted and should not be planted too deep – an inch or two below the surface is fine. Typical spacing is around 18 inches or 45cm, though I have planted a little closer than that. We are also arranging the new canes in a double row to make the most of the available space. This can be worked from either side of the bed and I am hoping to see a good thicket of stems develop along the length of the bed.

The central bed of the fruit cage planted with raspberries.

We selected four varieties, three summer fruiting and one autumn. For summer we have Glen Moy, Cascade Delight, and Tulameen. These are early, mid, and late season sorts respectively so as to spread the harvest. Our autumn fruiting variety is once again Joan J. We were so impressed with the quality of the fruit from our old fruit cage that we had to have this one again. In fact, if limited in space such that we could only grow one sort, it would certainly be an autumn rather than summer raspberry and Joan J would be at the top of the shortlist.

We haven’t yet decided on what sort of support to provide. There are various possibilities due to the use of the old polytunnel frame as the fruit cage surround. Raspberries do not really need much help, just something to keep their stems more or less contained. It may be that some arrangement of canes or strings will suffice but that is a problem for another day. For now, the soil has been transformed – though a few more years of mulching will be needed to really develop it – and the canes planted. We bought 10 canes of each variety from Ashridge Nurseries, which had the varieties we wanted and at good prices. The canes for Joan J were outstanding – an amount of good fibrous root that I have never before seen on raspberry canes. The others were a bit of a mixed bag, some canes were great, though not in the same league as Joan J, and a few were rather mean. I have always been a bit disappointed with bare root raspberries. Unlike my experience with other bareroot trees and shrubs, raspberries often seem to have a meagre bit of root, they are sometimes not much more than a dead stick and consequently can struggle to establish. Glen Moy offered a couple of very good canes, several reasonable canes, but three miserable specimens. I have little hope that two of them will establish and but a faint hope for the third. I planted four on one side of the bed, three good ones on the other and in the final position grouped the three dodgy canes together – hopefully one of them might grow there or we will be left with a hole in the row until they start to fill out and I can transplant something into that position. Time will tell just how good the canes are – by late spring we should have an indication. They will probably need some irrigation to establish well, especially on this free draining sandy soil, and that is something I must attend to. Perhaps a soaker hose on a timer might be in order.

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