Friday, November 20, 2009

Damping Off

Young plants in seed-beds often perish suddenly from a rot of the stem at the surface of the ground. This occurs as a rule in dull, cloudy weather among plants kept at too high a temperature, crowded too closely in the beds or not sufficiently ventilated. Several kinds of fungi are capable of causing damping off, under such conditions.

Preventive measures are of the first importance. Since old soil is often full of fungous spores left by previous crops, it is the wisest plan to use sterilized soil for the seed-bed. When the young plants are growing, constant watchfulness is required to avoid conditions that will weaken the seedlings and favor the damping off fungi.

Watering and ventilation are the two points that require especial skill. Watering should be done at midday, to allow the beds to drain before night, and only enough water for the thorough moistening of the soil should be applied. Ventilation should be given every warm day as the temperature and sunshine will permit, but the plants must be protected from rain and cold winds. Work the surface of the soil to permit aeration and do not crowd the plants too closely in the beds. If damping off develops something can be done to check it by scattering a layer of dry, warm sand over the surface, and by spraying the bed thoroughly with weak Bordeaux or by applying dry sulphur and air-slaked lime.