[Paulj]

I just got a 300litre barrel from my MD second company.  It's sealed at both end at the moment, but on one end there are two caps that I could use to let rainwater in through, however I do not have a shed or other building to divert water from into it, will not have in the future.  Everyone else on my allotment site seems to have similar barrels, but with no top on at all presumably for similar reasons, but I wondered if there would be any value in leaving the top on the barrel before I dive in to sawing it off (but I would remove the caps to let rainwater in?

If I do leave the top on the barrel I assume it will take longer to fill as there will be less top open to collect water, but am not sure that is realistically a problem in our climate.

Also we do have running water from April through to September.

[JayG]

If the top of the barrel is recessed so it will collect the water across its surface it will of course drain into the barrel if there is a hole in it, but you will still only get a 1 inch depth of water for each inch of rain that falls (average rainfall in Nottingham about 25-30" per year?)

If the top is shaped such that it can't collect water then the amount you collect will be reduced by the area of the open caps divided by the area of the top of the barrel (not promising, even in our climate!)

The ideal is of course to provide a bigger catchment area, but assuming that's impossible then sawing off the top and putting it back on upside-down would at least help keep the water clean and maybe reduce evaporation.

[RichardA]

no top means far more likely to go green and collect insects though no top also means can add things such as manure in a sack or comfrey to make liquid feeds
R

[gavinjconway]

Cutting the top wont give you any useable amount of water...  If you have some space get some plastic sheeting and use it to collect water then divert into the barrel. I would lie the barrel on its side with a bungs vertical top and bottom.. then fit a tap to the bottom one. The top one removed for water to enter..

Place a pole in the ground at each corner and have the two back poles longer to form a sort of an angled roof to collect the rainwater. then tie a pipe into the lower section "valley" with gaffer tape or bicycle tubing and divert into the barrel..  

or stand it up and let the sheet dip into the open bung. Then drill a hole in the bottom and fit a tap.  

If you have a plastic sheet of say 4' x 6' it will only take about 6" of rain to fill it.. so the bigger the better.. Maybe a couple of conservatory roof sheets would be good heated up with a gas torch of sorts to make a shallow valley.. 

Keep your eyes open at all times for stuff you can use on the plot.. especially skips..
See my artists drawing... well sketch..

[Paulj]

Thanks Gavin. That looks like a good idea.  I'm taking my barrel down to the allotment tomorrow so will plan to allow space for that idea. Brilliant timing.

[gavinjconway]

Thanks Gavin. That looks like a good idea.  I'm taking my barrel down to the allotment tomorrow so will plan to allow space for that idea. Brilliant timing.

Hope the sketches helped... I forgot to say you need to add some weight to stop it flapping in the wind..