Wooden balcony planter-composter, 50 x 50 cm

Add your raw or cooked peelings without sauce or dressing, coffee grounds and tea leaves with the bags split open, crushed eggshells, mushroom peelings, and faded leaves and flowers. Keep meat and fish, pasta, bread and brioche, oil, milk and citrus fruit out of the composter, along with garlic, onion and leek, which act as worming agents, and walnut and rhubarb leaves. Grass clippings do not belong there either: their volume exceeds what the composter can take, and this input, which is very rich in nitrogen, rots for lack of oxygen if it is not mixed with dry material.

Kitchen scraps bring mainly water and nitrogen, whereas sawdust brings dry, carbon-rich material. A handful of sawdust after each addition absorbs excess moisture and maintains the aeration the worms need, which prevents fermentation smells: a balanced compost smells of woodland. The material should stay as damp as a wrung-out sponge, never soggy. The 2 bags of 400 g supplied are for getting started, then a bag of wood shavings for composting takes over as you keep adding waste.

A compost worm eats roughly its own weight in material every day, but an established colony can go 3 to 4 weeks without being fed. A summer absence therefore does not endanger the composter, provided the unit stays in the shade during the hot hours, since above 30 °C the temperature can be fatal to the worms. The planter, on the other hand, depends on watering: before leaving, water thoroughly, fill the drip tray to create a reserve, and ask a neighbour to look in once a week during hot spells.

The plants in the planter need regular watering, more often during heatwaves, when you can also fill the reservoir. An olla planting pot buried in the planter releases water through its wall and extends the time your crops can go between waterings. As for the compost bin, worm activity slows outside the range of 15 to 25 °C; stand the unit against a wall of the house rather than against the railing, which softens the cold in winter, and keep adding waste through the cold season, in smaller quantities.

The planter is grown like a raised bed: herbs, salad leaves, strawberries or flowers settle in easily, and you arrange them from the tallest at the back to the lowest at the front, so that each one receives light. Replace each plant as soon as you have harvested it, so that the planter stays full and produces throughout the season. A set of organic salad and chard seeds lets you sow several successive batches, and the compost produced alongside keeps the soil fertile from one batch to the next.

The composter is emptied roughly once a year, through the side hatch provided for this purpose. The compost is ready when you find almost no worms left in it, a sign that decomposition has run its course; allow about 6 months at the start, while the colony multiplies, then 3 months once it fills the whole composter. When the composter is full, a compost activator speeds up decomposition by about 30% for a month, and the annual accessories pack includes two bags of it along with the year's sawdust. The harvested compost goes into the planter when you replant, or into your other pots on the balcony.

The Balcony arrives assembled from the workshop: the pre-assembled wooden square with its tarpaulin base and overflow, and the stainless steel composter with its lid, set on the drip tray. The starter kit includes 2 sachets of 400 g of sawdust, a batch of composting worms, the composting guide and an instruction leaflet. The unit is made in Alsace, and all you have to do is put it in place, fill the planter and make your first deposit.