Are they outside? I left mine outside for seven days when they were only one week through the soil. At the site they only get around 7 hours of sun a day which meant they weren't baking for 12 hours a day in sun which probably helped. But, they were in crappy soil which could have hurt- it was a seed starter, mostly peat and very little real nutrition and didn't hold water long.
They were in 6 oz grow cups- the kind that the roots supposedly grow through eventually. I set them in a shallow plastic container with a lower profile than the grow cups so they would get sun but not fall over. The cups were up against each other inside the plastic container. That container had a few holes in it so water would drain. I went to Walmart's shoe lace section and bought the flat, wide, white shoelaces that I believe are nylon. Then I tested by cutting off the ends laying one end in a cup of water and the other laying in a dry cup. Sure enough, it was pulling water. On second thought it might be good to leave the tip on the end that plugs into the plant soil so you just press that down but press it deep so that pure lace is in the soil. So, I took a couple the rubbermaid or Glad type food storage containers to the site and filled them with water. The square/cubicle kind are better because the tops don't close down completely as they do on the round ones. The idea with that is not to choke off the water transferring through the nylon wick. So in the one corner where the lid has the flap or overhang I made sure was up and not pressed down completely.. this happens on its own with the particular ones I was using. I made sure there was enough shoelace in the water container that it was resting on the bottom with extra and then buried the tip of the other end an inch or so deep in the grow cups. The idea though is to position everything so that there is not much distance between the water and plants so that the water doesn't have to travel far and perhaps evaporate. The soil actually pulls water through the wick I believe. I took a gallon of water and had mixed a small amount of fertilizer knowing they'd need more food than was in that soil mix. If yours are already in good soil don't worry about it. From that gallon I filled the Glad food containers.
Can you picture that and is it making sense?
When I returned seven days later the cups were dry but the water was mostly gone from the containers so I felt they had received some benefit. We had no rain while I was gone. The plants were healthy and didn't look stressed although the soil was dry. I watered them completely before I left but I doubt they survived the seven days of sun just on that so I tend to believe they got some extra water out of the "system".
You need:
4 cup cubicle containers- Glad
Shoelaces
A larger container that holds your pots up if they won't stand on their own. My starter pots were like small cups and would fall over without a brace. If you are already in decent sized pots then you probably don't need anything else.
