Water Crystals AFTER growing/planting?

[JMSinATL]

Hi everyone!
This year is my first time growing tomatoes, and I'm doing it in 5 gal buckets. (Many holes drilled in the bottom and lower sides for drainage.) Silly me thought "oh, I'll keep up with watering, no need for those nifty water-holding crystals or the potting soil with them!" Well, fast forward to now, and GA's had 90+ degree weather for weeks now. I've missed a couple waterings but tend to water heavy when I do, and usually I water every evening. That said, I spent the weekend away and my waterer didn't water the plants, said he forgot. Is it feasible to put some of the water storing crystals in the buckets now, when the plants are about 3-4' tall with lots of fruit? Or should I look into a drip system of some sort? Any and all feedback appreciated. FWIW, I used the Miracle Grow Organic Choice potting soil, with some Mater Magic at the roots. I planted 2 each Bush Goliath, Patio, and Roma. Thanks in advance.