A recent lab test shows that the major nutrients in my vegetable garden soil are all very high, except for the nitrogen. The potassium was measured at 814 ppm, whereas the recommended level is apparently 50-250 ppm. The lab said that the high potassium level was interfering the plants' ability to utilize other nutrients. A 50/50 mix of manure/compost was applied to the vegetable bed last December. No weeds grew in it in the spring, which was somewhat odd. After rototilling in May, I planted vegetables as usual but most seedlings turned red and died soon after germinating. Tomatoe and broccoli transplants grew very little after being planted. The dismal plant growth prompted the lab test. Does anyone have thoughts on how to correct the potassium problem?