What are key events I shouldn’t miss when growing this crop?

Depending on the greenhouse location and desired finish time, shipping liners for transplanting will happen between late September and early December or early in the new year.

Plant growth regulators (PGRs) should not be required to slow the stretch of growth because we select lavender varieties with controlled habits suited for specific pot sizes. Depending on the variety and whether or not natural light and temperatures can help control the growth, PGRs may still be useful. PGR availability depends on regional registrations. 

Consult with your Qualitree account manager for further information.

What soil do I need?

A well-drained peat-based substrate is best. 

The pH range should be 5.0–5.5.

What kind of environment do I need?

A cold greenhouse (heat at 3ºC/37.5ºF, vent at 5ºC/41ºF) with constant airflow. The crop can heat up naturally with the weather nature provides as the plants start to wake up at the beginning of February through to finishing in flower.

Southern growers may be able to keep the lavender crop outside for the duration of the cycle.

Do not place hanging baskets over the lavender crop, as all the light available is required to ensure a uniform finish. Spacing the plants is important for health and growth.

When can I expect buds or color?

Color is dependent on variety and weather. On average, our earliest variety will naturally show color in week 13, finishing in week 15, while later varieties will finish around week 17. Utilizing greenhouse lights and heat can encourage earlier flowering if the natural environment does not already allow for that.

Using heat without the addition of light will lead to stretched and weak growth, with a poor showing of flowers.

What kind of fertilizer strategy should I have?

Lavender requires continual fertilization throughout its growing cycle, including during the rooting phase during fall and once dormancy breaks.

This is most easily managed by applying liquid fertilizer and maintaining the substrate EC level between 0.8 and 1.2 (measured using the 1:2 dilution method). When choosing a fertilizer product, ensure it contains calcium, boron, iron, and a general micronutrient package.

Opt for balanced fertilizer with an N target of 150ppm when growing cold. 

Increase to 200-250ppm in circumstances where:

• You are pushing growth with additional temperature and light
• Flower buds are visible. Maintain through to flowering.

This fertilizer is ideally 2:1 nitrate-form N to ammoniacal N.

We prioritize nitrate nitrogen over ammoniacal nitrogen to keep growth firmer, substrate pH in check, and pest susceptibility reduced. 

What kind of pests should I anticipate?

• Aphids
• Leafhoppers
• Bacterial leaf spot
• Pythium
• Phytophthora
• Botrytis