Unfortunately, there's no easy answer to this question, as you've already discovered. The true answer would be "right before they start to wilt." This is something even experienced gardeners get wrong sometimes, though. It's like saying you should swerve right before the deer jumps out!

Until you get to know your plants better, here's a vague guideline, the "1, 2, 3." Week 1 = probably every day, week 2 = every 2 days, week 3 = every 3 days, etc... until you reach about week 7, once-a-week. As your plants grow, their roots will go deeper into the soil, allowing them to obtain moisture for a longer distance through the soil. So, as time progresses, you want to water longer and less often. I think it's better to err on the side of not often enough once plants are about a month old. If the ground feels moist, watering shouldn't be necessary. The search for moisture makes the roots probe down and out, so only help when they really need it. Wilting is a sign to water immediately.

Feel down about 1". Is it moist? Then don't water. If it's borderline and tomorrow is going to be a scorcher, go ahead and water.

As you get the feel for your soil and the conditions, you'll do better and you won't have to check so often.

While we are on the subject, mulch, mulch, mulch. Once summer kicks in we won't see much significant rain but lots of moisture-sapping sun. Mulch helps a lot. I used about 10" of straw or the equivalent and by mid-summer there isn't much left.

Thank you so much -- this is (as usual) very helpful. I bought a soaker hose, and I think I'll follow the 1, 2, 3 model until I get a better idea of how to do this right.

Again, thanks.

Remember that tomatoes need more water than most plants. It's also important for them to have pretty consistent moisture, so be sure not to let them get too dry, This is another reason to use plenty of mulch, which will help maintain the moisture level. Just don't put any mulch right up against the stalk or trunk of any plant or tree as this encourages insects and diseases to get into the stalk Also, you'll need to water more often in hot, sunny weather or if your plants are growing in pots.

Watering 'on a schedule' is not ordinarily a practice that will lead to healthy, productive plants. All of the plants you've mentioned are thirsty plants, as you will soon discover.

Soil type, plant species, temperature, humidity, amount of sunlight, age and size of plant, weed competition, etc. are just some of the factors involved in the frequency of watering. You'll also need to consider the amount of water given during each watering cycle. If the soil doesn't get saturated completely and deeply, then you'll need to water more often, especially as the plants mature.

Remember that veggies require lots of water in order to make all of that delicious food for us. You can't scrimp and expect to enjoy lots of produce.

If you do mulch, and I'm all for that, make sure that you apply enough water to get through the mulch layers to the soil. It takes quite a bit of water (or rainfall) to do that.

I would FEEL into the soil ( not just the surface) until you can judge the watering need without getting your hands dirty. Be sure to explore the soil where there is no soaker hose to make sure that the water is working its way horizontally though the soil, and not just wetting a vicinity near the hose.

I prefer drip systems to soaker hoses. They take a little more brain sweat up front but coverage is more controllable (less watering the weeds) and I like that you can add misters or other kinds of moisture options for plants that like that, for example, ferns.

I would spend a year or two in your garden before making the investment, but once you do watering becomes so much easier.