Answer: Sunscreen fabrics are not solid but are loosely woven fabrics so some sunlight will penetrate and some rainfall will trickle through. If you keep the fabric at least 12" above your plants you will still be able to water them as usual and the fabric will still provide some shade to your plants. I attach sunscreen fabric to stakes in the bed, about 3' above everything and angled so rainwater falls off and yet the fabric still provides afternoon shade. This method might work well for you, too.
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