It says the practice died away after mains-supplied water was introduced, but with pressure on water supplies the demand for rainwater recycling systems is rising again.
He advises people can also use "grey water", the water from a kitchen sink or bath to feed plants, but says it should be used straight away and not stored.
A rainwater harvesting system is a "more serious" alternative to a water butt, says Terry Nash, from the UK Rainwater Harvesting Association.
Continue reading the main story How to fit a water butt:
Groundwater is redistributed to the Mediterranean biome and outside biome, while the rainforest biome relies on rainwater, collected in the tank, "percolated" and pumped out via an irrigation system.
"The storage tank would almost invariably be underground, out of sight and be 10, 20, or 30 times the content of a water butt," he says.
"Or if you add half a teaspoon of cooking oil, a film spreads across the top of the water also preventing them from breeding.
Overnight in the South West, Exeter Airport recorded 29mm of rain, more than half its previous April average of 56.4mm. The UK-wide average rainfall in April 2011 was 36.7mm, and 48mm in 2010.
With heavy rainfall drenching parts of the UK and hosepipe bans in place, what's the best way to store water to feed your garden?
• Increase your storage by connecting several water butts together, or just get one larger butt if space allows
• Buy a water butt from your water company, gardening or DIY centre
But the water should only be used on the garden, Jacob Tompkins says.
Sales of water butts have already been surging as hosepipe bans have been enforced, as it is estimated that about 24,000 litres can be saved from the average house roof every year.
He also suggests cutting the bottom off a plastic 1.5 or two litre fizzy bottle and burying it upside down near plants, to get rainwater straight to their roots.
"Plants prefer rainwater, as tap water is chalky and rainwater is acidic." He recommends joining more than one butt together to maximise storage.
"People shouldn't drink water from the butt, as rainwater is fine, but what's collected on your roof isn't – it can be contaminated but deposition of particulates on the roof from pollution and cars."
And the wet weather is set to continue, with the possibility of as much as a month's worth of rain falling in Wales and the south of England over the next few days, the Met Office says.
"You should not have problems in the UK with mosquitoes, but if you do, there are special gels and crystals you can add to your butt to stop them breeding.
The easiest way is to sever a plastic down pipe with a hacksaw and place the butt directly underneath it – an overflow pipe can be attached to the butt to channel away excess water to a drain or into another butt Alternatively, cut a notch out of the pipe and fit a rain trap and connecting pipe – this will transport water to your butt and allows you to put it in the most convenient place
However they are more expensive.
Gardeners have been given a much-needed lifeline to keep their plants alive over coming months.
A lid is needed on any water tank to prevent debris entering it, but also to prevent children falling in. It needs to be secure, and children need to be aware it is heavy, he says.
But he says for home gardeners, even before harvesting water, there are decisions to be made about how it is used.
Alistair Griffiths, its horticultural science curator agrees there can be risks gathering rainwater at home.
Nash says if someone had bought a system and installed in three weeks ago, it would be full by now.
While the wet weather continues, water harvesting will remain a top priority for gardeners, as experts say it isn't enough to bring parts of the UK out of drought just yet.
There are two ways to fit a water butt:
"They are the simplest and cheapest thing to do," he says, "it just fits in to your downpipe. You can gather water in buckets and watering cans as well, if you use it straight away.
So how can one make the best of it?
The Environment Agency's tips for collecting rainwater are:
Although it takes 12 years to get "pay back" from them economically, they are "the right thing to do environmentally", says Waterwise managing director Jacob Tompkins.
"If your gutters are not clean, or there's a build-up of stuff in them, that can cause disease in plants if you use the water on them, especially seedlings," he explains.
The Eden Project in Cornwall is one garden that tries to store as much water as it can all year round.
Rainwater from the Eden Project's biomes is used to irrigate the site at night
Griffiths says the water harvesting and distribution system at the Eden Project has been "designed specifically to capture as much water as possible from its biomes' roofs".
Andy Berry, from Acorn Landscapes in Gloucestershire, says some people choose to go "the whole hog" on systems costing tens of thousands of pounds.
"They install a rainwater storage system with filters and pumps, so the water can then be used safely in their house," he says.
Plants prefer rainwater as tapwater is chalky
• Fit a water butt on every downpipe on your house, shed, garage or greenhouse
The concept of capturing rainwater and storing it for later use is well-documented from pre-Roman times, the UK Rainwater Harvesting Association says.
"They would have filled a 6,500 litre one… because we've had so much rain over the last four weeks."
"Don't over-irrigate, as it can make plants not resistant to drought… and don't water in the middle of the day, if you water at night there's less opportunity for sunlight to evaporate it,"
Continue reading the main story Where to store rainwater: Standard water butt: Holds between 100 to 300 litres, is a barrel or square shape and has a tap near the base Ornamental tank: Designed to fit in with your garden (shaped like boulders etc). Capacity is between 30 and 300 litres Large above-ground tank: Holds up to 2000 litres, and is a big rectangular shape, that needs to be sited on a flat firm base Large underground tank: Can store several thousand litres of water and requires a pump. Because of size can be connected to washing machine and toilet too