Our Guide to Watering Lavender

We’re frequently asked by visitors to our farm about how to water plants like lavender, rosemary, and helichrysum.   Here is what we do.

One of our key goals is to grow healthy plants that produce a good harvest of flowers, while using as little water as possible.  To get there, the frequency and amount of watering is critical - and this is different for a small vs mature plant.  Even though a mature lavender needs very little water (and can be exceptionally tolerant of long drought periods), the four inch “starter” you bring home from a nursery needs time and “training” to become hardy.  

A young lavender plant must be provided with specific conditions to encourage development of deep roots as fast as possible.  How you water affects root development, and strong, deep roots increase tolerance to drought.  It is particularly important to get watering right during the plants first summer in the ground.  We follow a specific pattern of irrigation – which we only modify when mother nature provides rain. 

The basic approach to proper watering is soak & let dry.

Assuming you plant in the spring (say April or May), you should begin by watering once per week (maximum twice per week if it happens to be relatively warm and dry right after planting).  Direct the water to the base of the plant, don’t shower over the foliage.  A drip system is ideal, because it applies water slowly, giving time for the water to penetrate deep into the soil column.  If you don’t have drip irrigation, ensure the water soaks in at the same rate you are applying it.  Water should not run away over the surface.  Your goal is for the water to move down into the soil to a depth below where the roots currently reside.  About a quarter of a gallon is about right for each watering of your 4-inch plant during its first month in the ground. 

During the second month, apply twice as much water, but only water half as often - so one-half gallon once every two weeks. 

At month three, you should further stretch out the time between waterings to only once every third or fourth week - but now give approximately one gallon at each watering.  Continue at one gallon, once every 4 weeks, for the balance of the summer, or until cooler/wetter weather sets in at autumn, when you should stop watering. 

Year Two and Beyond: If you have followed this practice, the plant will have produced relatively strong & deep roots in its first season.  If you continue from the second summer forward with the same practice of soak & let dry, once per month, the plants roots will reach further into the soil column and become even more resilient. 

Evenings, or very early in the morning, are the best times to water.

If you are growing lavender in pots, water when the soil is completely dry 2-3 inches down from the surface.  Pots require more frequent watering, but worse, restrict root development - so the plant can never become as strong as it would in the ground.  So lavender, rosemary, helichrysum, etc. tend not to be happy in pots very long, and especially not over the winter - so do yourself (and the plant) a favour - find a sunny, free draining spot in the ground and let them flourish.