Introduction to Commercial Lavender Production Propagation, Planting, Soils, Weeds & Much More! By Dr. Curtis Beus, WSU Extension, Clallam County
Lavender Propagation
The Art of Cloning
Propagation •Lavender should always be propagated from cuttings to maintain the true characteristics of a particular cultivar. Lavender grown from seed will not be consistent. •Lavandins (Lavandula x intermedia) such as “Grosso” are sterile and cannot be propagated from seed •Some lavender cultivars are easy to root and others are not. •Semi-hardwood cuttings can be taken in Spring or Fall (and, if source plant is properly managed can be taken nearly year-round). Softwood cuttings may be taken in Spring.
Lavender tissue culture is relatively easy, but beyond the means & needs of most growers Semi-hardwood cuttings
Propagation
Cuttings Semi-hardwood cuttings
Mix 50% potting soil and 50% fine perlite for new cuttings to promote good drainage.
Propagation
Dip into rooting hormone
Scrape one side of the cutting
Bottom heat, misting, cool ambient temps, will speed rooting
Cuttings ready to grow
Depending on cultivar & condition, rooting will usually take between 3 and 6 weeks
It is Critical to Keep New Plants Properly Watered
But, over-watering cuttings and young plants causes plant stress and can lead to various disease problems. You must also be sure to use a very “light�, porous planting mix. In some cases of you could lose your entire crop. Therefore, you must be careful not to over-water. Plants should be kept moist, but not saturated. Healthy Plants
Sick Plants
Humidity and air circulation are very important when young plants are being grown out in the greenhouse Poor air circulation and/or high humidity leads to fungal diseases
Soils & Soil Fertility for Lavender
Soil Textural Triangle Size of Soil Particles Sand
.05 - 2 mm
Silt
.002 - .05 mm
Clay
Less than .002 mm
Lavender does best in well-drained, lowclay soils
There’s More to Soil than Topsoil A Horizon
Topsoil
B Horizon
Subsoil
C Horizon Substratum
Nielton Very Gravelly Sandy Loam
Schnorbush Loam
Soils & Soil Fertility for Lavender Production
“Light” Sandy, Sandy Loam, Gravelly and Even Rocky Soils are best Soils MUST be well-drained “Heavy” soils with high clay content are typically poor for lavender production Check the subsoil -- not just the topsoil – hardpans can lead to poor drainage If soils are not well-drained, plant lavender in mounds or berms, and/or install a drainage system It is often best to plant on slopes and high places in the landscape -- avoid low spots, especially on more poorly drained soils If drainage is very poor, installing drainage systems might be necessary Soil pH should be between 6.0 and 8.0 -- 6.5 - 7.5 is ideal
Soils & Soil Fertility for Lavender Production Check pH before planting -- if pH is below 6.5, apply enough lime to raise pH – periodically check pH and add lime if pH falls below 6.5 Amending large areas of soil is very expensive and often ineffective If subsoil is compacted, fracturing it with a deep chisel can significantly improve drainage Conduct soil test before planting -- correct major deficiencies Nitrogen applied at 90 pounds per acre (split between spring and post-flowering) can increase canopy development in first 3 years If used at all on mature plants, nitrogen should be applied at no more than 40-50 pounds per acre Over-fertilization may actually reduce oil yield and quality and make mature plants less healthy, hardy and drought tolerant
Soils & Soil Fertility for Lavender Production
Over long periods of time lavender can deplete soil nutrients and necessitate rotation to other crops to renew soils Keep organic mulches away from base of lavender plants Light colored soils, or mulches of white sand, oyster shells or other light colored materials may increase oil yields and improve plant health, especially in more humid climates NZ studies have found that the longest-lived lavender is found on locations that have: 1) 2) 3) 4) 5) 6) 7) 8)
north-facing mid-slopes (that would be south facing for us) light, well-drained soils with low organic matter high stone/gravel content low active calcium stable soil structure without compaction low available phosphorus medium available magnesium low to medium available potassium
In “Heavy” or Poorly Drained Soils it is a Good Idea to Plant Lavender into Berms/Raised Beds
You may even need to install drainage
Soil Preparation Sequence at My Farm
Soil Preparation Sequence at My Farm
Planting Lavender
Mix 50% bone-meal and 50% composted chicken manure – add 1-2 cups
Cut the bottom roots, especially if root-bound
Mix bone-meal and chicken manure with the soil
Press soil firmly around new plant & water immediately
Planting Sequence at My Farm
Plant Spacing • 4 - 7 ft. between rows – 5 - 6 feet most common • 2 - 4 ft. between plants – 36” - 42” most common • 2,000 - 4,000 plants per acre -- 2,500 is the average (3’ x 6’ spacing will yield 2,400 to 2,500 plants per acre)
• Adequate spacing is necessary so plants get needed sunlight, air movement, and for ease of weeding, harvest, etc.
Establishing Plants • “Harden” plants before planting in field • Fall planting best in mild climates*—with bigger plants (not plugs) • Spring planting is OK, and is often the best option in areas with harsh winters** • Clip flower buds for first 2 years to get plants well established *Fall establishment is often better because it is often the “slower” season, and because roots can get established and give plants a “headstart” for the next Spring **Better quality plants are often more available in Spring, with a bigger selection available Unless you know what you’re doing and have the time to carefully monitor and care for them, it is best not to plant plugs directly to the field
Clip Flower Buds for the First Year,, and Possibly even Two Years!
Clip Flower Buds for the First Year,, and Possibly even Two Years!
Buying Lavender Plants •
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Plugs -- 72 plug tray $.60 to $.75 wholesale – about $45 to $55 per flat 2 ½” pots -- $3.00-$4.50 retail, $1.10-$1.50 wholesale 3 ½” pots -- $4.00-$6.00 retail, $1.50-$2.50 wholesale 1 gallon -- $7.00-9.00 retail, $3.50-$4.50 wholesale Make sure to buy healthy plants Know what type of lavender you want before you buy MAKE SURE YOU ARE BUYING WHAT YOU THINK YOU’RE BUYING – a lot of confusion & misidentification of lavender varieties
Cost of plants can run from $2,000 to $12,000 per acre, depending on size of plants
72 Count “Plugs”
3 ½” Pot
2 ½” Pot
2 ½” Pot
Plug
Irrigation • •
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Drip irrigation is recommended Irrigation is Critical in the 1st year, and often essential in the 2nd year Irrigation may increase production in mature plantings In dry climates, and/or with fast draining soils, irrigation will be necessary, even for mature plants Overhead sprinklers are suitable for plants early in the season, but once stems have elongated and flower heads are becoming developed, sprinklers may cause plant and/or flower damage. There is also the risk of bacterial and fungal diseases, particularly in more humid conditions. Although lavender is a drought tolerant plant, it often benefits from irrigation, especially in light soils and during dry years – but, be careful not to over water! Irrigation after harvest can stimulate added shoots for next year’s crop The amount you will need to irrigate will depend greatly on your soil type, and on your local climate. I.e., hot, dry areas with sandy soil will irrigate FAR more than cooler, rainier areas with heavier soils.
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