What to do about strawberry lack of potassium and magnesium in greenhouse

1. Potassium deficiency: Symptoms of potassium deficiency in strawberries often occur in the upper leaves of new maturity. Black, brown and dry edges often followed by burns, but also in most of the leaves between the veins to the center of development, old leaves seriously damaged. Light can aggravate leaf burns, so potassium deficiency is often confused with sunburn. True petioles of burned leaves often develop brown to dark brown, with slight damage, then gradually wither. The fruits of potassium deficient strawberries are light in color and poor in taste. Control methods: apply sufficient organic fertilizer, about 7.5 kg potassium sulfate per mu; also spray 0.1%~0.2% potassium dihydrogen phosphate solution 2~3 times on leaves, spray once every 7~10 days, spray 50 kg fertilizer solution per mu each time. Magnesium deficiency: initially upper leaf edge yellowing and browning scorched, and then interveinal chlorosis and dark brown spots, some spots developed into necrotic spots. When scorch aggravated, the stem leaves appeared light green and swollen, scorch phenomenon developed with the increase of leaf age and magnesium deficiency. Generally, strawberry is easy to appear magnesium deficiency when cultivated in sandy land or excessive application of nitrogen and potassium fertilizer. Control methods: foliar spraying 1%~2% magnesium sulfate solution 2~3 times, every 10 days or so spray once, spray fertilizer solution 50 kg per mu each time.