Water storage

Our watering makes all the difference to most of our crops, and with some much more than others. Such as over-wintered brassicas and early sown carrots may crop well without extra water, even in a drought year, as their roots delve deeper following winter water down as it falls. Well established trees and soft fruits, vines and figs can likewise crop well without extra watering especially if well mulched in humus rich soil. But for the majority of vegetable crops and many of our fruits good attention to watering will very significantly improve the yields. And of course salad crops, plants under cover and plants in containers need copious and continuous watering.

The problem is having enough suitable water. Usually mains water is rather too cold, heavily chlorinated, possibly fluorided, frequently loaded with dissolved salts which leave chalky deposits, expensive and, worst of all; may be prohibited in those drought periods when we need water the most. Thus gardeners need to store their rain water. Preferably that winter water which, with climate change, we are soon to have even more of.

Currently each roof in the UK receives at least half a metre of rain and some nearly three metres a year. That’s a lot when stored. Without guttering the garage, and the dog-shed your house alone produces a huge amount. Simple maths will give you yours- you can work it on your ground floor measurements, the slopes balance each other out, they have more area but only receive the same rain as a flat surface, with more on one side and less on the other. As most rain over most of the UK comes from the South West so that side of the roof generally needs bigger gutters and down-pipes! Anyway at least half a metre or more falls on average on every square metre of roof on every building. One having, say just four by five metre length walls, covers twenty square metres; which means that roof runs off at least ten cubic metres of water, often twice or three times that. And that is an awful lot.

But unfortunately although most already comes in winter, climate change predictions suggest we will get even more in winter and even less in summer. Thus larger scale storage becomes even more necessary than in the past when you could rely on the odd summer thunderstorm to fill your butts up again. From now on one or two water butts will help but rather insignificantly so. They run out too quickly and it will be too long before they’re refilled. What you need to do is to put in as many as you can fit in. Fortunately water butts do not need be that accessible, or even visible. They can be connected together with hose-pipe which if fitted as syphons means that most can be hidden away in inconspicuous places. In any garden you will have unproductive spots, often in shade, where butts can be sneaked in. Between hedges and fences, under huge old hedges and conifers, behind sheds and garages, even as garden walls. I have a dozen and a half- and they’re still not enough!

(Syphons- if a water butt receiving water has it’s overflow directed to another butt through a hose pipe then that will fill it too. But when you empty the first butt the water can not return to replenish it. However if the overflow pipe is replaced with a hose pipe with ends that drop inside to the bottom of each butt and this is filled with water (use the mains pressure from another hose pipe, or suck) then the water flows backwards and forwards. It always reaches a level that is exactly the same in both butts -so these may need to be set into the ground a bit or raised up on blocks on sloping sites. Once set up with siphons connecting all your butts then water from a down pipe can enter any butt yet fill all of them. And then amazingly as you use water from any one it will automatically refill. You never need carry water far- I’ve put small butts (plastic dustbins) in my greenhouse and polytunnel and by the nursery beds. Not to catch or store but to receive water so I can draw down on the whole system right where it is to be used, and all without a pump. Having small butts under cover also allows these to pre-warm the water you are about to use. Normally these stand on blocks when the system is full. As the water is used the level drops till inconvenient then the blocks are removed, the dustbin lowered and it fills deeper. If rain falls the system fills and the dustbins are raised on blocks again. Syphons usually keep themselves going but may block or occasionally air bubbles form. Simply restart the siphon with a mains hose.)

(Butts- Of course you don’t need set up a huge interconnected water butt siphon system immediately. Just another butt or two will be useful for a start even if not enough by far. So do think big, or rather more, as more water will always be handy. Conventional water butts vary widely in price and volume- bigger usually works out much less per gallon. There are alternatives that can work out cheaper still. But first consider a bulk buy; research and see what reductions you can get for buying a half dozen or more. Usually the more you buy the much cheaper they get so go in with friends and neighbours and get a lorry load. You all need them anyway. Second hand may be better than you suspect; old steel butts and oil drums get discarded when holed yet are now easy to refurbish. Wire brush the inside till shiny, fill the holes (turn it over and look from inside to spot them) with automotive plastic body filler or resin impregnated glass fibre for bigger ones. Then a coat or three of black bituminous paint and they will be as good as new. Dead deep freezer bodies can likewise be converted into excellent and surprisingly neat butts. You can throw away the lid for access, or retain it to keep out leaves (most of freezer body walls and lids are surprisingly easy to make holes through for pipes). Council reject and damaged wheelie bins can be found with broken wheel fittings or lids but still water tight. Kiddies inflatable paddling pools are wide and fairly shallow- and really cheap and I’ve one that is still waterproof after four years in the garden. Old wooden barrels are aesthetic but not awfully long lived unless well tarred. Then there are commercial plastic barrels and all sorts of containers for fruit juices and so on; these can be huge, rigid, or thin walled in wire cages. Often sold very cheap near where they are emptied. Some can also be stacked more than doubling your capacity- though this adds complications to the connections- to say nothing about the danger- that is a lot of weight you will accumulate so get it right.

Do stand all your butts on secure footings as they weigh a lot anyway, even a small one. Do consider children- water is always a danger to them! Do give every butt an overflow if not a siphon and take this to a proper soak-away far away from your foundations (there are building regulations; check with your local council). Or preferably take the water first into a water feature, bog garden or blueberry bed. All gardeners could consider delivering such over capacity water to soft fruit, vegetable beds, greenhouse borders or fruit trees, possibly through perforated drainage pipes or seep hoses. Though make sure your system can deal with the rush of a downpour.

If you have the space then it is not difficult to make very large water stores pretty cheaply. I find circular tanks can be made with walls of old car tyres laid like bricks and tied in a circles atop each other. The whole then held from popping out with a ring of wire netting for safety. Inside is fitted a plastic sheet to hold the water, naturally on top of several layers of padding (old plastic sacks, carpets, even cardboard –to blunt stones, deter moles etc. etc.) Cheap plastic sheet can be used but butyl is better and lasts longest if most expensive. Wider is easier than deeper as the pressure gets difficult to resist over waist high and could pose a flood danger in case of leaks- think carefully about your site.

Obviously it makes sense to clean butts when they accumulate residues. Lids help prevent leaves, birds and kids getting in in the first place. Old nylon stockings hung on down pipes catch the crud- which is valuable stuff for the compost heap. Even so some sediment always appears so it makes sense to inspect if not overhaul each butt every autumn making sure it is ready to carry it’s next load. Final tip- I put goldfish in most of my butts- they keep down the gnat larvae, and for sure a bit of fish poo must be good for the crops.