Why are my tomato leaves drying up?
I have been growing lettuces and herbs for a while now with good success so I though IÃ¢ÂÂd try tomatoes. I started with heirloom Cherokee Purple seeds and transplanted when they were a few inches high. I grow DWC (3 gals water) under full spectrum LED (200w, 5w bulbs ~18" away). GH Flora, Bloom, Micro ~800ppm, pH ~6.5. They initially grew thick stock and stems and large dark green leaves. About a week ago the leaves started to dry up (without turning brown). They would open up and within a day, dry up. The new leaves are also quite a bit smaller.
Any ideas? I read that heirlooms donÃ¢ÂÂt do well in hydro setups.