Granted, I pushed it, but that was my intent.I have been growing tomatoes--heirlooms, hybrids, cherry--inside, in my basement, in five or six-gallon buckets for the last five years. When I grow them outside, I generally check the water level about every two weeks, depending on the weather. When I grow them inside and I am home, I check them about every two weeks.
This year I started the seeds around Labor Day and by the first week in November they grew to about four feet. Strong stems. Good root system. And three of the four plants started to flower; one had already formed small fruit. One cherry tomato plant was set in a six-inch wide-lip basket (WLB). I placed about one inch of a peat-perlite mix at the bottom of the basket, set the plant, and supported it with only perlite to the top of the basket.
I travel out of the USA periodically and this year (2018) I was out for five weeks in sunny and toasty-warm Mexico. I had topped off each of the six-gallon buckets with some fertilizer (16-4-17) and a bloom-fruit booster called, Hulu. Hulu (0-50-40) is some potent stuff. You only use a half-teaspoon per five gallons.
By the way, you can use any hydroponic fertilizer with your soil-based plants, whether they are in containers or your regular garden. You cannot, or should not, use outdoor fertilizer with your hydroponic plants. No commercial or slow-release fertilizer has the range of nutrients, macro and micro, that hydroponic fertilizers typically have. You can use a bloom or fruit-type hydroponic fertilizer outdoors with your fruit or flower-bearing plants. Back to Mexico.
I set on my merry way thinking that the plants should have enough nutrient solution for at least three to four weeks, but I was not sure about five unattended weeks. This would be the first time I would leave them all alone without anyone checking on them. So it was with some apprehension when I returned to see if they were still living.
Surprise. Surprise. The plants had doubled in size and were banging into the rafters (nine-feet) and the LED units. And they not only had produced fruit, but the fruit was ripe and ready to eat. Fantastic.
My first task the next day was to whack off the tops of the plants by at least three feet, which would keep them well away from the ceiling and the LED units. Granted, the plants were spindly and they were not as robust looking as when I left. The key take-away for me was that while there was only about one-gallon of water left in each bucket, or not more than two-inches deep, the root systems had reached into that shallow remaining pool and kept the plant alive to the point that it was producing fruit.
While I am not recommending that you avoid checking on your plants for such a long period of time, you should be comfy knowing that if you are out on business or away from your plants for two to three-weeks, they should be fine. Grown outdoors, the main variable will be the weather. Will it spike to the upper 80s or low 90s? So, depending on your location growing your plants in buckets or ten-gallon totes, for example, should be okay for a minimum of two weeks and (perhaps) up to four weeks.
Low maintenance with high yields. No gardening experience necessary.