Ok, so I am going on holidays in 6 days for 8 days. Will putting a small hole in a bottle work or? Any suggestions will be great. I can't put them outside because of the photoperiod
I'm assuming you use soil. You can make a ghetto "water globe" out of a clean 20oz soda bottle. Fill it with PH adjusted water, jam it's mouth into the soil, and it should keep the soil moist for about 2 weeks. Quick tip. If you are going to be using anything besides pure water (nutrients/additives) make sure you LIGHT PROOF the bottle! Light and nutrient rich water don't mix well. Edit: When you get back, let the plants dry out for a couple days. The water isn't aerated so the roots will need to breath for 4-5 days.
Or you could run some fabric wicks into the bottom of your pot and set it in a bucket of nutrient filled water. It is the most basic of all hydroponic/terraponic systems aside from hand watering and could realistically keep your plant watered for up to a month. If you keep it in the tub I would do a nute and water change every week though.
Using rockwool because they're still in seedling stage. They're 2" cubes, so they don't hold water for long.
If you don't have a drip or an ebb & flow system ready to put them in then I don't have any suggestions. Not many things you can do with just a rockwool cube.