Watering vegetables is tricky because too little or too much water can do harm. Too little water won’t reach the deep roots of some vegetables, and too much water can compact soil, restricting root oxygen intake. In general, vegetables need 1 to 2 gallons of water per week, and deep, infrequent watering is the best way to ensure they get the right amount.

Root depth is a big factor in how long you should water your plants. Leafy vegetables, like chard, lettuce and beets, draw water from the top foot or so of soil, while deeper-rooting vegetables, like tomatoes and asparagus draw from at least 2 feet below soil level. Both root types draw in about an inch of water weekly, but deeper roots require more water to get through the layers of soil.

Plan to provide plants with 1 gallon of water every 5 to 7 days, and water again when the top inch or two of soil is dry. Check for dryness by grabbing a handful of soil and clenching it in your fist. Moist soil sticks together and dry soil crumbles apart. Apply more water during hot temperatures when the soil dries faster. A deep watering schedule encourages deep rooting, while frequent, shallow watering is often inconsistent and results in shallow roots.

An easy way to measure water volume (especially in small gardens) is to fill a gallon jug from the hose and time how long it takes to fill the gallon. Water plants directly from the hose for that amount of time.

You can also measure watering depth to ensure you are watering correctly. Water to 24 inches for deep-rooting veggies, and 12 inches for shallow-rooting veggies. Insert a pole in the ground near your plant’s root and measure the depth of the water stain, similar to how you use a dipstick to check oil. Moist soil is loose, while dry soil is hard. If you can only insert the pole to 8 inches, for example, you are not providing enough water.

Remember to water your garden in the morning, before warm temperatures break to ensure that as much water as possible penetrates the soil instead of evaporating from the surface.