1. Chop squash, red pepper and onions. Place in a large bowl and sprinkle with salt, stir well. Let stand at least 1 hour.
2. Drain mixture in a colander, rinse and drain mixture two times pressing out any excess moisture with last draining.
3.In a large pot, bring vinegar, sugar, garlic, dill seed, mustard seed, celery seed to a boil.
4.Add squash mixture, bring to a boil again, stirring frequently. Reduce heat and simmer for 10 minutes.
5. Remove from heat, add the turmeric and mix well.
6. Pour into sterilized jars, leaving 1/2 inch head space. Seal with lids and rings. Process in covered boiling water bath in for 10 minutes. Remove lid and let sit 5 minutes before removing from water.
I like the squash, onion and red pepper chopped on the large side for this relish. Tastes just the same chopped small. So how ever you like it.