Swiss chard in a balcony box: how to keep the harvest going into winter
Swiss chard is the underrated marathon runner for balconies: tough, pretty and far more frost-tolerant than you'd think. With a few simple habits you can keep picking fresh leaves for quite a while yet.
While basil and tomatoes are long gone, there is often still a chard plant in full glory in the balcony box. It tolerates light frosts and keeps producing new leaves with the right care. Here is how to keep it going now.
Why chard is so rewarding in October
Swiss chard is a relative of beetroot and originally comes from the Mediterranean, yet it copes surprisingly well with cool weather here. It usually shrugs off light frosts down to around minus three degrees Celsius; in harder frost the leaves turn mushy. At temperatures between five and fifteen degrees it keeps growing slowly and often tastes milder than in high summer.
Harvesting the right way: outer leaves first
Always pick the outer, larger leaves and leave the heart of the plant with its young leaves in place. That way chard keeps growing from the center. Twist the leaves off with a small sideways jerk or cut them just above the soil. As a rule of thumb, leave at least four to five leaves on the plant so it keeps its strength.
Removing yellow and mushy leaves
In autumn some leaves turn yellow or develop brown spots, often caused by leaf spot fungi in persistent damp. Remove such leaves regularly and put them in the household trash or the organic waste bin rather than the compost if they are heavily affected. This keeps the plant airier and lowers the risk of fungi spreading.
Watering: little and in the morning
In autumn very little evaporates, so chard needs much less water than in summer. Check with your finger: if the soil is still moist two inches down, wait. Water in the morning so the leaves dry before evening, and make sure no water stands in the saucer.
Frost protection: fleece and mulch
If the forecast calls for nights below minus three degrees, cover the box with garden fleece and lay a thin layer of leaves or straw around the plant. A box on a balcony freezes through faster than a bed, so move it against the house wall. Before several days of hard frost, harvest the largest leaves; they keep for about three to four days in the fridge.
And it continues in spring
If the chard survives winter, it resprouts in March and gives you another round of leaves before it flowers in its second year. In Rootivo you can note in the garden journal when you last harvested and how cold it was, so next year you can see how far your chard got.