<aside> 💡 People always ask me where they can buy the things I mention in this book and my videos, I now have a solution for you, I’ve listed these items in my Amazon Store. The store includes comments on most items, please read these! Sometimes I refer you to a cheaper place to buy than Amazon for example.
This chapter should be read in conjunction with the chapter on growing under cover which explains why I use raised beds, coldframes, low tunnels and various netted frames as well as why I also use a lot of nets and fleece.
<aside> 💡 Rather than repeating myself, when I'm referring to multiple types of structure (coldframe, low tunnel etc) I'm just going to call them frames the bases that these frames screw onto I will call raised beds, these just stack on top of each other to make coldframes
You might also like to read the chapter on learning to grow under cover, which is part of the section of the book on self-sufficiency.
I'm not going to provide a cost breakdown for these various frames in this chapter, because life's too short. However rest assured that my allotment easily pays for itself and makes a large profit. I did invest £300 when I did the initial build, many years ago, but that investment was easily paid off within a few months of harvesting. When I spent £1000 on my big high tunnel in March, the allotment harvests had paid that back by June of the same year. I no longer track costs, because harvest savings are always way higher.
<aside> 💡 In order to make these structures pay back you need to harvest a lot of food all year round. All of these frames are expensive to make though and if you can't afford them, you can get a good approximation of the results I enjoy with fleece, hoops and plastic.
Personally because we harvest so much and hence save so much on our bills, I never think cost, I always work to increase harvest volume/quality and minimise effort, making a profit looks after itself.
If you want to dig further into the economics of an allotment I have a lot of videos on this topic that will keep you busy!
You need to make some material choices before you start making your frames. Here are the basic options and recommendations:
I generally recommend buying new, because it's unlikely that you will be able to standardise the design of your allotment (see later) if you use recycled materials. Recycled wood in particular is almost always untreated and it won't last very long, new treated timber will typically last well over ten years above ground and maybe 8-10 years in contact with the soil.
The only option I would consider is recycling polytunnel plastic and using it for cold-frames and low tunnels. After 7 years it might not be great for a polytunnel, but it's probably got a lot of life left in it for a coldframe top.
I always use treated timber. A few decades ago the chemicals used to treat timber were not great for growing plants, but new standards in the UK seem to be much improved. I've found no evidence that there's any leaching into the soil from the timber sides and since you never plant that close I'm happy myself, but you need to make up your own mind.
When you cut wood make sure you treat the cut ends, in fact I treat the uncut ends too. I put wood preservative in a bucket and stand the ends of planks in it for 30 seconds, it soaks about 2" into the wood.
When you screw into the wood make sure to dab plenty of preservative around the screws, this also soaks into the screw hole.