Straw Bale Garden

A straw bale garden grows a crop in a bale of straw instead of in the ground. The bale is the pot and the soil at once: roots run through the straw while the straw rots down around them, so by the end of the season the bale has become compost. That separates it from a raised bed, which is a frame holding soil brought in from elsewhere. It grows food where the soil is poor, thin or absent, and asks almost no building skill. Straw is used rather than hay, because hay carries weed seed.

A fresh bale will not grow anything. It has to be conditioned first, over about two weeks of daily watering and concentrated high-nitrogen fertiliser, heavy at first and then lighter, sometimes with lime near the end. The fertiliser wakes bacteria that eat the straw from the inside, and the bale heats as they work. Schedules differ - twelve days in one, ten in another that asks the inside to reach about 71 degrees Celsius (160 F) - so the bale is the test rather than the calendar. It is ready once that heat has passed and the straw feels crumbly; a transplant set into a bale still hot will die. Choose the spot before conditioning starts, because a soaked bale is too heavy to move.

The upkeep is heavier than the low skill floor suggests. A bale holds little water in reserve and dries quickly, and a dried-out bale cuts the harvest, so it wants watering close to daily. The rotting straw also draws nitrogen away from the crop - yellowing leaves are the sign - so a complete feed every month keeps the plants ahead of it. Tall crops need staking, since loose straw grips a root ball poorly, and the bale makes dry shelter for mice and moles. The hazard that outlasts the bale is herbicide: some weedkillers used on grain crops stay active in straw for years, so a contaminated bale grows deformed plants and then becomes compost that spreads the problem. Expect one season, sometimes two.