I have the strangest problem this year. All my plants in a 6 X 10 raised bed are falling over when they reach maturity. They seem to be well anchored in the soil but for some reason they simply want to lay down. It almost appears as though the lower stems/stalks get weak and can't support the plant upright. My hollyhocks have all fallen over; my nice State Fair zinnias have all fallen over and even the dahlias have fallen over. The plants all look extremely healthy and have bloomed beautifully. I'm wondering if I could have a problem with the soil. It's 1/3 compost, 1/3 mushroom manure and 1/3 poor soil. Could the soil simply be too rich? Or possibly although it doesn't appear to be obvious to me, could insect be eating the roots. I'm doubtful that it's insects because the plants have been all falling down uniformly. Or maybe I have some kind of root rot? Can anyone help me with this problem? By the way, I'll be sending a soil sample to the soil lab for testing later this fall. Thanks again for any help.