You definitely have to raise your plants off of the ground. They will soak up leftover run off nutrients and the bottom of you pot will be full of salts and be ‘hot’. I’m growing in 20% soil and 40% coco 40% perlite. You want run off when growing in coco, they advise 10-15% run off to help rise out unused nutrients in the bottom of the pot. Here is a good read about PPM and run off.
https://www.amazon.com/dp/B01J37FHF8/ref=twister_B01KHZJKG2?_encoding=UTF8&th=1
Gro Pro NX Level Pot Elevator - 13"
Gro Pro Plant Saucer, 12-Inch, Black
That is a great option for keeping your plants out of run off water. I use a Stanley 4 Gallon Wet Dry Vacuum to suck up the run off water from the saucers.
I wouldn’t buy these things from amazon because my local hydroponic store carries them at a MUCH cheaper price. The Elevator’s were under $3 each at the local store, $10 on Amazon. Same for the saucers. Except for the shop vac… I can only find that one on Amazon, and all my Home Depot and Lowe’s carried inferior vac’s at a more expensive price, so I ordered from Amazon.
Check out my Organic grow I just started. Going to transplant into 5 Gal Vivosun fabric pots when I have about 3-5 nodes.