This post is about the next phase of our "standard beds" project. As you may recall, we have standardised our beds to a layout of 25' x 4'. Each bed is therefore 100 square feet. The beds are deeply manured and can be worked from either side (weeded, planted etc.) without having to step on and compress the soil.
Another reason we wanted to "standardise" our beds was that we have realised over the years, that some of our crops need protection or assistance. Some forms of that predation are insects (Cabbage white butterfly caterpillars eating our brassicas), birds eating our fruit etc. Other forms of protection and assistance we would like is to protect from frost, warm the soil etc. This would take the form of "cloches".
The problem with these protective structures is that good husbandry dictates that we "rotate" our beds, growing different things in different beds each year. This helps both to prevent pests (by not providing their favourite prey in the same place repeatedly) and with nutrition (by planting different plants that require, or provide, different nutrients in succession).
In order to both protect our food, but allow for rotation, we have decided to build standard protection structures that can be moved between beds as we move the crops around.
We decided to make structures similar to small polytunnel frames in a standard layout. These frames could have a variety of coverings added to them to provide protection from birds, insects etc. We set a number of objectives for our design
1) They had to pack flat for storage when not in use
2) They had to be able to be moved and erected by one person
3) They had to be "modular" so that half or a whole bed could be covered.
The basic materials used in the beds were
A) 20mm HDPE conduit (bent over to form the "hoops" of the tunnel)
B) 2inch plastic waste pipe
C) lots and lots of 2" x 2" pressure treated timber to make a central "ridge support" for the tunnel
D) a variety of screws
E) Conduit clamps
F) Joining plates
Tools needed are
A) A Hacksaw to cut pipe
B) A steel tape measure
C) A marker pen for pipe
D) A chippies pencil for marking wood
E) A panel saw for cutting wood
F) A mitre box for cutting angles
G) Drill and drill bits
H) A screwdriver, power driver or socket driver
I) A drain / rabbit spade for digging narrow holes
J) A lump hammer for hitting things
H) 2 large G clamps
1 - Conduit and pipe by
British Red, on Flickr
2 - 2"x2" by
British Red, on Flickr
So, the first thing I did was to cut up a load of 2" waste pipe into 10" lengths. These lengths will be buried at the edge of the beds to form "sockets" into which the legs o the hoops can be inserted. They will be left in place, even when the frames are removed making subsequent erection of frames a much quicker job
3 - 2" waste pipe by
British Red, on Flickr
The next job was to work out how high and long to make the central ridge support for each tunnel. The 2x2 I have is in 3 metre lengths so we decided to make each tunnel "module" 3m long
4 - Goal post plan by
British Red, on Flickr
Doing weird maths to anticipate how high the bent conduit would end up (it is also 3m lengths), was...just too hard!
I decided to just set a hoop up and do it empirically...so to the veg beds! I took along a drain spade (to dig a narrow hole for the waste pipe "socket"), a hammer (to tamp the soil around the socket firmly) and a tape measure to site the sockets
5 - Hoop sleeves and tools by
British Red, on Flickr
I dug a narrow hole about 9" deep (to leave an inch of the pipe above the surface)
6 - Hoop sleeve buried by
British Red, on Flickr
The soil was tamped firmly back around the pipe with the club hammer
7 - Tamped in by
British Red, on Flickr
The end of the pipe just showed proud from the soil
8 - Sleeves left in place by
British Red, on Flickr
A 3m length of conduit was bent over and one end inserted into each socket
9 - Hoop in situ by
British Red, on Flickr
Then, to work out the height of the central support, I just measured from the apex to the soil
10 - Measure Goal Post Height by
British Red, on Flickr
This measured 104cm. I added 26cm for the element to be driven into the soil and added the dimensions to the plan
11 - Add height to plan by
British Red, on Flickr
Knowing the uprights needed to be 130cm I measured them out
14 - Measure 2 x 2 to length by
British Red, on Flickr
I used the mitre box to cut a neat point on the end of each upright
15 - Cut points on uprights by
British Red, on Flickr
I measured where the uprights would come on the cross member and marked them up to screw the uprights in place
16 - Mark up butt joint by
British Red, on Flickr
Putting the cross member on some sacrificial wood I drilled some pilot screw holes
http://www.flickr.com/photos/british_red/6935342188/
17 - drill pilot holes on sacrificial wood by
British Red, on Flickro
Sometimes I do use power tools - but to be honest, there is no need. A socket set with good adaptors makes a great screwdriver set
18 - driver set by
British Red, on Flickr
Drill bits work fine on all drills - and we should all have a full set and plenty of spares of the common ones
19 - Drill bit set by
British Red, on Flickr
On this job a brace and bit or hand drill would have been just fine. I often find them handier as there are no batteries to go flat, or extension cords to run.
The one advantage of power drivers and drills is the ability to hold the workpiece with one hand and drill / drive with the other. More clamping is required when working "solo"!
Anyway, I placed the cross member on the upright, drilled pilot holes through the cross member and into the upright, then screwed the two together with 4" wood screws.
19 - Suprights lettered and marked by
British Red, on Flickr
After screwing on the other upright, I was left with a "goal post" structure
21 - Goal post roughed out by
British Red, on Flickr
Using the mitre box I used scrap 2x2 to cut corner supports and clamped them in place.
22 - Corner braces clamped by
British Red, on Flickr
The corner braces were screwed in place with 3" screws
23 - Corner braces screwed by
British Red, on Flickr
This left the completed "goal post" structure looking like this
24 - Goal post complete by
British Red, on Flickr
On the leg of each goal post I marked the depth that it needed to be driven into the soil
25 - depth marked by
British Red, on Flickr
The goal post was aligned to the centre of the bed at one end and (using a piece of sacrificial wood as protection), the uprights driven in to the required depth
26 - goal post knocked in by
British Red, on Flickr
The position of each hoop was marked with a pencil
27 - conduit position marked by
British Red, on Flickr
A conduit clamp was centered and screwed in place with an inch and a half screw
28 conduit clamp by
British Red, on Flickr
29 - conduit clamp attached by
British Red, on Flickr
The conduit clamp was used to secure the conduit to the central "goal post" apex support
30 - conduit clamped by
British Red, on Flickr
Three "hoops" were attached to the apex support. They should not be more than 4' to 5' apart or the net will sag
31 - First frame completed by
British Red, on Flickr
A second frame was placed at the other end of the bed
32 - Second Frame by
British Red, on Flickr
Clearly these frames can be used independently - singly or in pairs - but on this occasion I wanted to cover the entire bed. For this I wanted to connect the two frames.
For this I used a piece of 2x2 with a joining plate at each end - this was screwed to both frames
33 - Joining Piece by
British Red, on Flickr
This creates an "entire bed" frame
34 - Whole Bed covered by
British Red, on Flickr
For crops that require insect pollination but bird protection (e.g. strawberries), a wide mesh will cover the frame to let the bees in but keep birds out. These will be held in place with releasable cable ties.
36 - Bird Mesh by
British Red, on Flickr
You may note this is a high quality knotted cord net - not cheap polythene stuff - its stronger and lasts for years.
For keeping insects off cabbages, brussels etc. a much finer mush will be used
35 - insect mesh by
British Red, on Flickr
For cloches, a lower frame will be used and covered in clear polythene - but of a small greenhouse was wanted, this height of frame could be used.
Red