Detailed Explanation of Key Points of Soilless Cultivation Techniques for Lilies
Lily Propagation Methods
To produce high-quality lily cut flowers, the primary requirement is vigorous, disease-free bulbs. Lily propagation (also called "bulb production") can generally be divided into post-flowering bulb nurturing, bulblet propagation, scale cuttings, bulbil propagation, seed sowing, and tissue culture. Several main propagation methods are introduced here.
(1) Post-flowering bulb nurturing, also called large bulb propagation method. When lilies begin to flower, the new underground bulb has already formed, but has not yet developed into a mature "large bulb." Therefore, when harvesting cut flowers, while ensuring flower stem length, retain as many leaves as possible to facilitate the nurturing of the new bulb. 6-8 weeks after flowering, the new bulb matures and can be harvested. Whether subsequent forcing cultivation succeeds depends entirely on the maturity of the new bulb.
(2) Bulblet propagation On the nodes below ground level of the lily stalk, several bulblets will form. These bulblets have a sound root system and can be planted separately to cultivate into commercial cut flower bulbs. Initially, the bulblets can be planted in plastic boxes, using a mixed substrate of peat, vermiculite, and fine sand in a 2:2:1 ratio for cultivation. After one year, the grown bulblets are then planted in cultivation beds or ridges. Bulblet cultivation requires more fertilizer; the principle of fertilization is little and frequent, while nutrients should be complete. Mixing slow-release organic fertilizer into the cultivation substrate is an ideal fertilization method. During the second year of bulb cultivation (commonly called bulb cultivation), some will produce flower buds; these flower buds should be removed promptly to facilitate the cultivation of the underground bulb. After 2 years of cultivation, the bulblets can be used as flowering bulbs. After harvest, they should be graded according to specifications, diseased bulbs removed, and packed in boxes.
(3) Bulb scale cuttings Using vigorous scales for cuttings is one of the methods for propagating lily bulbs. The cutting substrate can be peat:fine sand = 4:1, or pure peat. Insert 1/3 of the scale (or 3 cm) into the prepared substrate. After insertion, keep the substrate moist; avoid waterlogging and high temperatures to prevent scale rot. Maintain the temperature at 22-25°C and relative air humidity at around 90%. There are no special requirements for sunlight, but long-day conditions are more favorable for the formation, growth, and development of bulblets. After 2 weeks, visible small bulb-like protrusions appear at the base of the scale; after 3 weeks, 1 or several fleshy roots gradually grow from the base of the bulblet; after 1 month, small leaves can emerge, and it becomes a bulblet capable of independent life.
(4) Tissue culture propagation Lily tissue culture is relatively easy to succeed. Explants that can be used for tissue culture include scales, leaves, bulbils, floral organs, young stem segments, root segments, etc., with scales being the most convenient. Peel off the middle portion of scales from healthy, disease-free bulbs, disinfect them, and inoculate them onto a pre-prepared culture medium. For different lily species or cultivars, hormone concentrations and types vary. For example, first use MS medium + BA 0.3 mg/L + NAA 0.1 mg/L to induce bud differentiation from the material. Then transfer to rooting medium MS + NAA 0.8-1.0 mg/L + BA 0.2 mg/L for continued culture, which can produce large numbers of daughter bulbs. Lily culture conditions: temperature 22°C-26°C, light 1000-1200 lux, 10-14 hours of illumination per day, medium pH 5.6-5.8.
Lily Scale Cutting Propagation
1 New bulb roots 2 New bulb 3 New bulb aboveground leaves
Bulblets propagated by the above methods still require 1-2 years of cultivation to reach the size for forcing cultivation.
Cultivation Management
Taking the cultivation of cut flowers for the March-May period, which is the most in-demand in the cut flower market, as an example, lily soilless cultivation usually adopts the substrate trough planting method, with the organic ecological soilless cultivation method being more suitable. The cultivation substrate can be prepared by mixing peat, leaf mold, sawdust, mushroom residue, vermiculite, perlite, bone meal, plant ash, etc. with organic solid fertilizer into an ideal composite substrate. The suitable pH is 5.5-6.5.
For lilies that need to bloom in March-May, the low-temperature-treated bulbs can be taken out successively from early December of the previous year to late February, and planted in batches. As long as management is proper, they can bloom on schedule.
Planting density varies depending on factors such as cultivar, bulb size, and light. For bulbs of grade one and above, no less than 40 cm × 30 cm; for grade two bulbs, no less than 30 cm × 20 cm. Planting depth is generally 3 times the bulb diameter; too shallow can easily cause lodging. After planting, if the substrate is relatively moist, there is no need to water immediately; watering 6-10 days after planting is more conducive to early new root growth.
After planting, maintaining the appropriate temperature in the greenhouse is one of the important conditions for good lily growth and flowering. For the first 15-20 days, the soil temperature should be maintained at 15-18°C; this temperature range is most suitable for root growth and leaf development. If the temperature exceeds 22°C, flowering is easily delayed or flower quality declines.
After 3-4 weeks from planting, the plant grows from sprouting to a height of 10-15 cm; this stage is the vegetative growth period. During this period, light and fertilizer-water management should be strengthened, watering with nutrient solution 1-2 times per week or spraying foliar fertilizer once, to promote leaf differentiation and growth.
When more than 10 visible leaf nodes are present, the flower bud differentiation process has already begun, and the plant transitions from vegetative growth to the reproductive growth stage. This stage is crucial for cut flower production. In cut flower pricing, the more flowers per stem, the higher the economic value. Factors affecting the number of flowers per cut flower stem, besides bulb size, are also directly and closely related to the cold treatment method and duration, cultivar, greenhouse forcing temperature, rooting speed and root quantity, light intensity, and fertilizer-water management during forcing cultivation. In cultivation management techniques, applying foliar topdressing when most plants are in the undifferentiated flower bud stage can significantly increase the number of flowers per stem. The method is to carry out foliar fertilization on 2 consecutive days: the first time with 0.1% potassium nitrate, the second time with a mixture of 0.05% ammonium sulfate plus 0.1% potassium nitrate.
From the visible small flower buds in the terminal leaf cluster to the opening of the first flower bud is the fourth stage. This stage is mainly controlled by temperature; under normal cultivation management conditions, it takes 30-35 days.
In cut flower production, besides staged planting, the leaf unfolding speed can also be used to regulate the growth and flowering period, that is, on the basis of basic leaf formation, temperature is used to control leaf elongation speed to achieve appropriate regulation of the flowering period.
Cut flower lilies should be harvested after 2-3 flower buds have shown color. Harvesting too early will lead to poor opening of flower buds, and some flower buds may even fail to open. However, harvesting too late, when flowers have already opened, pollen easily disperses and contaminates the petals, reducing flower stem quality; opened petals are easily damaged during harvesting and packaging, which also greatly reduces the selling price of the flower stems. After harvest, the flower stems are sorted, grouped by the number of flowers per stem, made into bunches of 10 stems each, with flower buds facing upward, wrapped in packaging paper, and packed into cardboard boxes for market.