|Field in early July, before flowering.|
Water deeply and infrequently for the best growth, just as you would for deep rooted trees and shrubs. If you have an automatic lawn watering system that "mists" the grass every day or two, the lilies will eventually receive too much water, so locate them just outside of the spray zone. The same holds true for flower bed sprinklers and drip irrigation. Most perennials and annuals like more moisture than what the bulbs require, so be mindful of how your water is distributed. Choose a spot for lilies where the sprinklers or emitters do not saturate the soil.
In the photo, do you see how dry our field rows were in early July last year? This section of the farm has a nice clay loam that drains well, but it is slippery when wet and builds up under your shoes. Always check for soil moisture before you drag over the hose to give lilies a drink.
Expensive electronic "water monitors" are not necessary. Just your bare finger will do as a monitor; if damp soil clings, then the ground is still moist enough. If your glove-less finger comes out clean two inches below the surface, then it is time to water. Be sure to provide enough water so that the soil is evenly moist down to the level of the basal roots (at the bottom of the bulb) or to about 8 to 10 inches deep.
Watering pots is a bit different; set your containers into a bucket or mortar box (used for mixing cement) to reclaim the water for the next pot if you only have a few to water. If your containers are not on a deck, but rather sitting on a sheet of plastic topped by bark mulch (to keep down weeds), then excess water can drain, and will be retained by the mulch to keep the pots cooler during hot weather. The only downfall is that you will give mollusks perfect conditions to multiply, so don't forget the slug bait around the pots, or a couple of resident ducks to root out slugs and provide eggs and entertainment.
Will you be short on water this year?
If you are in a dry climate, have a garden with very sandy soil, or live where water restrictions are imposed, you can still grow lilies. A two to three inch mulch of bark, ground leaves or other insulating material will help to save money and even out the moisture content of your soil. You need to include the depth of the mulch when determining how deep to plant your lily bulbs - 5 to 6 inches total of soil and mulch over the top of the lily bulb is about the maximum for most varieties. However, you can plant a little deeper in sandy soil. So, if there is 4 inches of soil over the top of the bulb, then 2 inches of mulch or ground up leaves would equal 6 inches total. With fluffy mulch, you can add more because it will tend to mat down over time. The idea is to give the stem roots enough space to grow underground, without making it too difficult for the sprout to emerge in spring. The extra mulch will also encourage beneficial earthworms in your garden as well. You can always add more mulch if necessary.
If the bulbs receive too much water during times of plenty or with saturated soil, the lower leaves will turn yellow and drop off, even before bloom. If that happens, pull away mulch that may be keeping the soil surface too wet, and allow the excess moisture to escape. A nicely mulched garden is beautiful, tying the landscape together visually, but only an inch of finely ground bark is needed during wetter years to cover the soil and help keep weed seeds from germinating.
Tips for conserving moisture in the Lily Garden.
Don't over water, always check the soil moisture first in your lily garden. Snap off the spent flowers as they fade, so that stems do not expend energy producing seed, and thus require more water. Top dress with well-rotted manure or compost in midsummer to provide nutrients to the stem roots and increase the amount of moisture-retaining mulch. When the leaves have begun to turn from green to yellow in the fall, cut the stem back to ground level and only water enough to keep the soil slightly moist while the lily bulbs are going into semi-dormancy.
Previous related posts:
Lily Bulbs not buried deep enough? What to look for...
How to increase "Red Wigglers" in your garden.
Controlling Slugs and Snails in your Lily Garden