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| Castor Bean Seedling Leaves Drying & Death |
Answered by: Inge Poot
Question from: Patricia Humphrey
Posted on: October 13, 1998
Four castor beans have sprouted. When the second set of seedling leaves start to develop on the stem, the first set on three of the plants are drying out, shrivelling and dying. I don’t see any insects or signs of diseases on the stems; the plants are getting a combination of natural and artificial daylight and are watered thoroughly when the soil is still slightly moist under the surface and I am not using any fertilizer in the seed starting mixture or in the water. Could the temperature be wrong for them - approx. 20 deg C during the day, approx. 18 deg C overnight ("night" lasts for about 8 hours)?
Castor beans germinate best at a temperature of 18 to 20 degrees Celsius, but once germinated, they grow better at 12 to 14 degrees Celsius. Also they are heavy feeders and would appreciate some fertilization. Lakefish fertilizer would work rather well.(Available from Richters under catalogue #T1030). When the plants don’t get enough food, they will remove nutrients from the lower leaves and transfer them to the newest leaves. The lower leaves then die. I suspect that is what happened to your plants’ cotyledons (first leaves).