rhubarb pesticide

rhubarb used as an organic pesticide

Rhubarb has been grown in British gardens for many years because it is not only a delicious food crop, used in desserts, but it is also a fantastically attractive plant. Traditionally gardeners have only grown rhubarb for the edible red stalks produced in early summer. The rest of the plant isn’t of interest to most gardeners and the huge deep green leaves of the rhubarb are generally just thrown on the compost lump.
The rhubarb’s leaves, apart from providing a beautiful visual in a vegetable garden, also possess a powerful and organic pesticide, named oxalic acid. Boiling the leaves (see below for recipe) releases the oxalic acid and this creates a liquid solution that can then be used like any other pesticide spray for insect infestations. This is a an organic solution and completely bio-degradable solution, however, care should be taken to not spray all insects indiscriminately, as it will also kill other essential natural predators , such as ladybirds and hoverfly larvae. Oxalic acid is a fantastic organic pesticide but it is also highly toxic to humans and will actually induce a cardiac arrest if ingested, so be very careful!

GROWING RHUBARB
Rhubarb appreciates a sunny spot and free-draining yet moist earth that has been well prepared and preferably double dug with lashings of well-rotted manure incorporated. Rhubarb can grow in soils with a pH of around 5 but does prefers a soil with a pH of 6.
Young rhubarb rhizomes (rhubarb crowns) should be planted out in early spring, just before active growth begins and remember that they become large plants, requiring a lot of space, so plant them at least 1metre apart. The area should be weeded and well mulched to prevent weed growth and maintain moisture levels.
Rhubarb insecticide
500 grams of rhubarb leaves should be added to a few pints of water and boiled for about 20 minutes or so. The remaining liquid should then be allowed to cool and then be strained the into a suitable container. Add some dish detergent or soap flakes (not laundry detergent!) and spray on leaves to kill off all kinds of bugs like aphids and spider mites.

* NOTE: Rhubarb leaves contain high amounts of oxalic acid. If ingested, your heart will stop and you will die.