How to Grow and Care for Calla Lilies

In calla lily cultivation, two methods are usually adopted: pot culture and trough culture. For pot culture, the compact, short white-stem type, red calla lily and silver calla lily are generally chosen; if large plants are the goal, the tall green-stem type or yellow calla lily can be selected. Calla lilies grown for harvesting the spathe as cut flowers are suited to trough culture.

Pot Culture Method for Calla Lilies

1. Soil mixing: The soil should be fertile, neutral or slightly acidic. It can be made by mixing 2 parts finely crushed pond mud (or fine clayey sand), 1 part leaf mold (or compost), plus an appropriate amount of superphosphate and decomposed human and livestock manure.

2. Propagation: Usually after flowering, the small corms around the tuber are peeled off and grown for one year, flowering the following year. Through testing, using the root-tiller division method, plants can flower in the same year. The specific method is: from late June to early August, while repotting, separate well-developed large divisions with roots by hand (best not to use a knife), and plant them in prepared pots. If used for cut flowers, 2 to 3 divisions can be planted together, and after planting, place them in a shady spot. Propagated this way, they can flower in September to October of the same year.

Planting Management of Calla Lilies

1. Nutrient solution management: For soilless culture of calla lilies, the following nutrient solution formula can be used: calcium nitrate 800 g, monopotassium phosphate 210 g, magnesium sulfate 250 g, potassium nitrate 500 g, ammonium nitrate 30 g, ferric ethylenediaminetetraacetate 10 g, manganese sulfate 2 g, zinc sulfate 1 g, boric acid 1.3 g, copper sulfate 0.15 g, ammonium molybdate 0.1 g. In the early growth stage of calla lilies, the nutrient solution concentration can be controlled at 1.2 ms/cm; in the mid-to-late growth stage it can be appropriately raised to 1.5 ms/cm. Throughout the entire growth period, the pH value of the nutrient solution must be adjusted to 5.6 to 6.5. The amount of nutrient solution supplied mainly depends on the weather conditions and the size of the plants; generally, the solution is supplied 2 to 3 times a day, ensuring that the cultivation substrate layer stays moist and that there is a shallow layer of water at the bottom of the trough.

2. Cut flowers: When the spathe of the calla lily has extended to its maximum, curled and opened, it can be harvested and cut. After cutting, the upper part of each cut flower should be wrapped in cellophane; after grading by size, they are packed and marketed. Fresh cut flowers should be handled with care during transport due to their own characteristics, to avoid damage during transport. For long-distance transport, about 20 bunches should be used as one transport unit; first put them in plastic bags and then pack them in boxes for transport. For short-distance transport, to save costs, only large plastic bags may be used; all of them should be fastened together with tape and then bagged for transport. During the process, they should be placed flat on top of a surface, avoiding being squeezed by other items and damaged.

Care Methods for Calla Lilies

1. Light and temperature. Calla lilies prefer a warm, humid environment with slight shade, but during the flowering period they need sufficient sunlight, otherwise the spathe will have a green tinge, affecting quality; 3 to 5 hours of light per day must be ensured, otherwise the leaf stalks will elongate and affect ornamental value. Calla lilies are not very cold-resistant and must be moved into a greenhouse in mid-October. In summer, under shaded conditions, they need frequent water spraying to cool down and retain moisture.

2. Watering and fertilizing. Calla lilies prefer moist, fertile soil, that is, what is often called “heavy fertilizer and heavy water”, and they need plenty of watering during the growth period. For topdressing, decomposed bean cake water and other organic fertilizers can be applied alternately with chemical fertilizers (compound fertilizer or diammonium phosphate), with topdressing every 2 weeks; when applying liquid fertilizer, be sure not to let the fertilizer water pour into the leaf sheaths, to avoid rot. Some people previously mentioned: “Stop fertilizing when flower buds appear.” After experimental comparison, the author believes that after buds appear, the amount of fertilizer should be increased, thereby ensuring a long flowering period, large and vivid flowers, and allowing the buds to keep blooming throughout the year.

3. Use of ferrous silicate. In potted calla lilies, topdressing with ferrous sulfate is an important part of the author's experiment. Topdressing with ferrous sulfate can make calla lily leaves larger, thicker and greener, smooth and glossy, and the leaf stalks are less likely to elongate, thereby ensuring the leaves look attractive. At the same time, it can promote bud formation and prolong the flowering period. The specific method is: dilute ferrous sulfate into a 2% solution and apply it once every month, watering thoroughly each time.