3 Quick Tips: Spring crop production QUICK TIP 1

摘要

Check the growing medium pH level of your geraniums. The plants may look just fine, but the medium pH can drop rapidly, raising the availability of iron and manganese to toxic levels. Geraniums are iron-efficient as are some marigolds, salvia, impatiens, gerbera, basil and tomatoes. They are able to acidify the medium around the roots. Toxicity symptoms appear as speckled brown foliage (similar to spider mite injury) and edge-burn and eventually the foliage turns yellow. Check the medium pH level atleast weekly. For zonal geraniums, the pH range for a soilless medium is 5.8-6.2 and for a soil-based medium it's 6.0-6.5. The optimal range for ivy and regal geraniums is slightly lower (5.5-6.2). If adjustments are needed, the medium pH can be raised with the use of flowable liquid limestone.