They will want a LIGHT dose of fertilzer soon. Don't overdo it; you can't flush outdoor plants in the ground, so less is more.
Try guano outdoors- seabird or bat. The grow time needs some higher Nitrogen, and I think seabird has that. During bloom, bat guanos with lots of Phosphorous are GREAT! Wild animals aren't as interested in digging up dried bat poop as they would be if you used bone meal, lol.
Or you could use a commercial chemical fertilizer. Look for one that is meant for cannabis, although tomato ferts are often used by outdoor growers with success.