The watering frequency indoor herbs need depends on testing your soil rather than a fixed schedule. Most herbs need water when the top inch of soil feels dry to your finger. This simple test works better than any calendar-based rule you might try.
I learned this the hard way when I killed my first batch of rosemary by watering it on the same schedule as my basil. My basil loved the daily moisture, but my rosemary rotted from too much water. Now I test each pot before I add water and my plants stay much healthier throughout the year.
Your rosemary, thyme, and oregano like to dry out between waterings. They come from dry climates with rocky soil. Let the soil dry down 2 inches before you water these plants again. Their roots will rot fast in soggy soil. When in doubt with these herbs, wait another day before you add water.
Your basil and parsley need more consistent moisture than Mediterranean herbs do. Check these plants every 2 to 3 days and water when the top inch feels dry to your touch. The University of Minnesota Extension warns that you should never let these herbs wilt from thirst. Wilting stresses your plant and leads to bitter-tasting leaves.
Knowing how much water for potted herbs to give matters as much as your timing does. Water until liquid flows from the drainage holes at the bottom of your pot. This ensures the entire root ball gets wet and pushes stale air out of your soil. Never leave your pots sitting in a saucer of water for more than 30 minutes after watering.
Your indoor herb watering schedule needs to change with the seasons throughout the year. Cut your watering back by 30 to 50% in winter when growth slows and days get shorter. Your herbs use less water when they grow less, so keeping the same summer schedule leads to root rot. Check your soil less often in November and more often again in March.
Root rot kills more indoor herbs than any other problem you will face in your home. The signs include yellowing leaves, a mushy stem base, and a sour smell from your soil. Once rot sets in, your only hope is to repot in fresh soil and cut away any damaged roots. Prevention through proper watering beats any cure you can try later.
The size and material of your pot affects how fast your soil dries out each day. Terra cotta pots dry faster than plastic or glazed ceramic because the clay breathes and pulls moisture out. Smaller pots dry faster than larger ones since they hold less soil mass. Factor these differences into your watering checks throughout the week.
Make soil testing a quick daily habit when you walk by your herbs in the morning. Stick your finger into each pot while you wait for your coffee to brew or breakfast to cook. Water the ones that feel dry and skip the ones that still feel moist to your touch. This takes less than a minute and keeps your plants healthy all year long.
Read the full article: Growing Herbs Indoors: Complete Guide
