Watercress is great for high pH in cooler weather or cool climates.
I've also grown plenty of tomato, eggplant, lettuce, kale, chard, broccoli, collards, kohlrabi, peas, basil, and many more things in a system that was hanging out at a pH between 7.6-8 for years.
Bananas also grew great as well as bamboo and water chestnuts.
Interesting, I thought basil grew at a low ph. My ph hangs right around 7.8 as well. Right now I'm fishless cycling. Before I add the fish should I try to lower it at all?
Nope. Don't be in a hurry or you will become a pH chaser. Once the system cycles it will start settling down naturally. You can plant early and add iron, potash and magnesium to help while you are waiting. Once the system cycles your plants will seem to explode in growth.
Thanks TC. my system was started april 1st so im praying for the explosion!!
the ph will come down.. my small first system - 110gal ft, 110gal gb's took between 8 and 11 months to drop from the high 7's to the low 6's,, i've since buffered it back up, but have been a little remiss in testing (just started buildout of system 3)