How to Grow Lilies And Other Plants in Clay
Growing lilies (and other plants) in clay can be difficult, but it can be accomplished. Lilies grow best when basking in sunshine, but with a shaded, cool soil that is moist, crumbly and well-drained. Clay soils are naturally dense, compact easily and do not drain quickly, causing the bulb to rot. Amend and berm the clay soil before planting the lily bulbs. Compost, well rotted manure, or commercial potting mix (such as our Power Grow blend with plenty of perlite) are the best materials to use to help break up clay. Gypsum alone will help but needs to be mixed with my recommended materials for the best results.
1. Choose an ideal area in the garden (such as a level grade or a gentle 5 to 10% slope) that does not tend to puddle or remain soggy after irrigation or rain. Avoid a depression or the base of a slope or hill because that’s where water will accumulate. Your planting area should receive at least six hours of uninterrupted sunlight daily. Some shading during this period is ok (such as caused from a tree limb, side of a building, other garden plants) but not too long.
2. Dig the soil with a shovel to create the lily planting bed. Cultivate the clay deeply, to a depth of 10 to 12 inches. It will be best to dig your spots for your lily bulbs in the Spring while the soil is wet otherwise, moisten the soil enough to make digging easier. Turn the soil, smashing and pulverizing all soil clumps…the smaller the better. Try to work so you don’t walk over the clay soil you’ve just turned over.
3. Place 10 to 14 inches of organic matter into the freshly dug clay soil bed. Scattering it in increments of 2 to 3 inches at a time, followed by mixing and incorporating the clay and organic matter. Mixing it with the shovel is easiest. Work the compost or well-rotted manure at least to the 8-inch depth. This organic matter improves the soil’s texture porosity and drainage. Afterward, the planting bed should be 4 to 8 inches higher than the surrounding grade. Allow the planting bed to naturally settle for a week or two before planting the lily bulbs. Follow our planting and care directions that accompany your bulbs. As a general rule, a lily bulb is planted two to three times as deep as the bulb’s height, often 4 to 6 inches deep. Space bulbs at least 16 inches apart. Air circulation around lilies is important, especially in gardens where moisture is abundant or slow-draining clay soil dominates.
4. Water the lily bulbs as needed being careful not to over water and rotting your bulbs. Lilies do not require a lot of water, only enough to keep the soil damp. You want the amended berms of clay soil to be evenly moist, never soggy or sticky in texture. Place a 2- to 3-inch layer of mulch over the mounded soil in the lily planting bed. Mulch shades and cools the soil in summer, reduces weeds, and conserves moisture.
Tips & Warnings
Once fall frost kills the above ground stems, don’t worry about irrigation. The dormant bulb is best left in moist to slightly dry soil in winter.
Gritty, larger-textured sand may also be added to amend the clay soil, but use it sparingly. Fine particles of sand and compost help make wet clay more like concrete once it dries.
Keep any mulch 2 inches away from the lily stems. This ensures good air circulation and prevents fungus or rot from occurring at the soil line on stem bases.