You may have heard of the patented Wall o’Water, a water-filled plastic insulating blanket. Put it around your organic vegetables and you can bring them in weeks earlier than usual. Works! But here’s a green gardening tip to grow organic vegetables faster, and it’s free.
Simply tie wine bottles together to form the frame of a round or rectangular tub. Fill the bottles with water, no need to cap them. Add compost to the frame and establish your plants.
The water in the bottles will absorb heat during the day and radiate it to the soil at night, even if the sky is cloudy, thus heating the roots. You will get much earlier plants, just as if you had grown them in a traditional hot bed heated with rotted manure.
To turn the BottleBed into an even more efficient (no manure) heated bed, simply push the canes into the frame and cover with clear plastic to make a bell. (One source of translucent plastic could be the sleeves that dry-cleaning stores use to protect clothing.)
With a BottleBed hood I was able to ripen tomatoes in late May, outdoors, in a temperate climate (zone 6) where outdoor tomatoes don’t typically ripen before the end of August.
A hidden virtuality
A hidden virtue of BottleBed is that it compels you to frequent pubs and restaurants to beg for your empty wine bottles or, reluctantly, buy a sneaky case of wine for the sake of your garden.
You can of course keep a BottleBed in place year after year. But beware: winter frosts can break thin glass bottles filled with water. (Champagne bottles seem curiously immune to frost.) Broken glass makes lettuce too crisp.
Solution: Use large plastic milk or cola bottles instead. A friend in Nepal emailed me that she was using BottleBeds to grow in the Himalayas before. I advised him: ‘Use plastic cola bottles, not glass!’ She said: “Sadly we now have a bunch of plastic empties – on top of Everest.”
Filled with water, plastic bottles survive the harshest frosts and last for years. They are easier to attach and hold firmer than wine bottles. Since it is the mass of water that conserves heat, not the containers, those large two-liter jugs filled with water are even more efficient insulators than glass bottles. It also doesn’t matter if the bottles are light or dark.
It works like a conventional cold frame.
In winter you can remove the soil from the frame and the frame remains rigid enough to use as a conventional cold frame, covered with corrugated plastic or an old window. Next summer, fill it with compost and grow early plants in it. And so on, year after year.
Colored wine bottles can be very decorative. But to disguise the ugliness of plastic bottles, surround them with burlap sacks or carpet clippings, or best of all, cover them with hydrotufa.
This is a compound of cement, sand, peat, and perlite or vermiculite that are put together to form a stone-like material. Other porous durable ingredients may also be used, as long as one-third of the mix is Portland cement. To make hydrotufa, mix equal parts of pre-mixed dry Portland cement and sand, peat, and perlite or vermiculite. Add enough water so that the dough is pliable without being runny.
Wait ten minutes for the chemicals in the cement to work. Then apply the hydrotufa around the bottles so that they form a stone wall. With practice, you can mold wet hydrotufa into highly decorative shapes or patterned surfaces. You can also color it with dyes or of course paint it.
Be careful: the hydrotufa is porous. Plants will take root in it. And it’s not very strong, so don’t try to lift a hydrotuff tub filled with heavy soil.
A BottleBed made from plastic milk or cola bottles, and disguised with hydrotufa, can be a thing of beauty. It will reliably produce plants much earlier in the season than usual. Best of all, it’s free.