Forcing technology for tulips, daffodils, and hyacinths in a greenhouse

Preventing defects and quality control in tulip forcing

To ensure that the flower stalks do not bend, stretch a plastic mesh with 12.5x12.5 cm squares over the plants immediately after planting. Raise it higher as the tulips grow. During the cultivation process, strictly control the substrate moisture and be sure to perform top dressing with calcium nitrate. To obtain high-quality cut flowers, regularly ventilate the greenhouse, especially during periods of high solar activity.

The appearance of "blind", discolored ("paper-like") straw-colored buds or dying flowers indicates technological violations. The main causes of such defects are the following factors:

• violation of the temperature regime during bulb storage;
• incompatibility of the chosen cultivar with the forcing schedule;
• use of bulbs that are too small;
• excessively high temperature in the greenhouse;
• insufficient duration of cooling;
• accumulation of ethylene in storage facilities;
• poor ventilation of the plantings;
• untimely removal of diseased and rotten bulbs.

The appearance of stems and buds directly reflects the growing conditions. Any deviations indicate specific failures in the technology. If defects appear, adjust the conditions in the greenhouse according to the table below.

Temperature preparation and forcing technology for daffodils and hyacinths

• Bulb cooling temperature — 5–9 °С
• Air humidity during rooting — 80–90 %
• Cooling period for daffodils — 16–18 weeks
• Cooling period for hyacinths — 10–12 weeks

Flowering times for daffodils are regulated by changing the bulb storage temperature after digging. Strict adherence to the regimes allows for obtaining cut flowers by the scheduled date. Adjust the temperature preparation according to the following table.

For hyacinths, temperature preparation of bulbs is also a key technological stage. Violation of storage regimes will inevitably lead to a shift in flowering times and loss of marketability. Prepare the planting material according to the provided scheme.

After the storage period is complete, proceed to planting. Forcing daffodils requires sequential execution of technological operations. Follow this work scheme:

1. Plant the prepared bulbs in boxes with an interval of 1–1.5 cm. The tops of the bulbs should rise 1–1.5 cm above the soil.
2. Maintain the cooling and rooting period for 16–18 weeks at a temperature of 5–9 °С and an air humidity of 80–90 %.
3. When sprouts reach a height of 5–7 cm, move the boxes to the greenhouse. Perform forcing at a temperature of 17 °С — flowering will begin in 12–20 days.
4. Ensure abundant irrigation during flowering. To maintain high humidity, spray the paths and the soil under the racks.
5. Cut the daffodils when the buds are in a half-opened state.

A different technology is applied for forcing hyacinths. It requires precise control of shading and air humidity at the initial stage. Follow this sequence of operations:

1. Plant the selected bulbs in boxes densely, without gaps between them.
2. Move the boxes for 10–12 weeks to a room with a temperature of 5–9 °С for cooling and rooting.
3. Two weeks before the expected flowering, place the boxes on racks in a bright room or greenhouse.
4. In the first week, be sure to cover the plantings with black film and water daily. Maintain a forcing temperature of 23–25 °С and air humidity of 70–80 %.
5. Cut the inflorescences in the half-opened bud phase.

After flowering, both crops require the same care. Water the plants moderately for 1–2 weeks, then gradually reduce irrigation and keep them at a temperature of 7–10 °C until the above-ground part has completely dried. After this, remove the bulbs from the soil and place them in storage until September — the optimal time for planting in open soil.

Forcing bulbous crops without using soil substrates is an effective way to obtain marketable produce with minimal costs for soil preparation. Narcissi and hyacinths develop successfully in vessels with water or a nutrient solution. This method allows for visual monitoring of the root system condition and helps avoid soil-borne infections during forcing.

Instead of plain water, a balanced mineral solution can be used, which accelerates the development of flower stalks and improves the quality of flowering. Salt dosages must strictly comply with the formulation to avoid burning the root system. The prepared solution is poured into a clean container immediately before placing the bulbs.

1. Prepare a narrow-necked vessel, if necessary, securing the bulb on a wooden disc with a hole corresponding to its diameter.
2. Fill the container with water or a working salt solution, maintaining a distance of 2–3 mm to the bulb's basal plate.
3. Place the container in a dark room with a temperature of 7–9 °C for 2 months for rooting, regularly topping up the water as necessary.
4. Transfer the plants to a warm room for forcing when the apical shoots reach a length of 7–8 cm.

By planting bulbs in October, the flowering of narcissi and hyacinths occurs precisely in time for the New Year holidays. This allows for planning product deliveries to meet peak seasonal demand. After the plants are sold, the containers are disinfected and reused.

Crocus forcing technology

Crocuses are valued in greenhouse production for their vibrant range of colors and short forcing periods. To obtain uniform flowering, it is important to follow the sequence of temperature treatments for corms during the dormancy, rooting, and forcing stages. Violation of the regimes at any of these stages leads to uneven development of flower stalks or their desiccation.

1. Preparation: dig up the corms in August and dry them for 10–12 days at a temperature of 20–23 °C.
2. Planting: in September, plant the corms in pots with a nutrient substrate in groups of 5–20, covering them with a 1.5–2 cm layer of soil on top.
3. Rooting: water the plantings and move them to a dark cellar with a temperature of 5–9 °C for 2 months, constantly maintaining substrate humidity.
4. Forcing: when shoots are 3–4 cm long, transfer the containers to a bright room with a temperature of 10–12 °C, and after 3–4 days, raise the temperature to 20 °C.

• Bulb drying period — 10–12 days
• Drying temperature — 20–23 °C
• Planting depth above the apex — 1.5–2 cm
• Rooting temperature — 5–9 °C
• Shoot height for forcing — 3–4 cm
• Period from forcing to flowering — 2–2.5 weeks

After flowering is complete, vegetative crocuses are handled the same way as other bulbous crops — narcissi, hyacinths, and tulips. They are gradually prepared for the dormancy period for subsequent propagation. This allows for the preservation of the planting material for future forcing cycles.

Integrating the forcing of small-bulb and bulbous flowers into the general turnover of greenhouse operations allows for the most efficient use of protected ground. Combining floral crops with the cultivation of early vegetables and mushrooms ensures continuous year-round exploitation of the areas. An agronomist can flexibly choose technologies and structures — from the simplest heated soil to modern greenhouses — depending on the farm's capabilities.

Sincerely yours, L. Shulgina ® From the author [Text omitted] Introduction... 5 Protected ground cultivation structures 11 Classification of protected ground structures 11 Which structures to choose 14 Heated soil 16 Hotbeds 19 Greenhouses 24 Site selection for protected ground structures 36 Properties of polymer materials for covering structures 36 Microclimate in cultivation structures 40 Lighting regime and methods of its regulation 40 Thermal regime and methods of its regulation 46 Soil and air humidity, methods of its regulation 56 Gas regime 59 Substrates and mineral nutrition 60 Nutrient substrates for ground-based vegetable cultivation 61 Hydroponics, or plant cultivation on inert substrates 64 Features of mineral nutrition 66 Plant protection system against diseases and pests 69 Growing seedlings of vegetable and melon crops for open soil 75 Biology features and seedling growing regimes 75 10 days of strict regime 78 Seedling demand 80 Timing and place for growing seedlings 80 Methods of growing seedlings 81 Preparing seeds for sowing 84 Seed disinfection 84 Treating seeds with macro- and microelements and growth stimulants 85 Warming up before sowing 88 Sequence of operations for preparing seeds for sowing 89 Features of growing seedlings in hotbeds 90 Features of growing seedlings in plastic greenhouses 91 Justification of heating methods 91 Soil preparation features 94 Seedling growing agrotechnics 99 Transplants of early white cabbage 99 Transplants of cauliflower 102 Transplants of mid-season white cabbage 103 Tomato transplants 104 Pepper and eggplant transplants 113 Cucumber transplants for plastic covers 115 Watermelon, melon, and zucchini transplants for plastic covers 115 Late cabbage transplants 116 Seedling quality indicators and regulation 117 Specifics of growing seedlings in an apartment and at a dacha 120 Personal experience of growing seedlings in an apartment and at a dacha 129 Recommendations for using purchased transplants 132 Vegetable crop cultivation 133 Cucumber culture 133 Some biological and morphological features of the cucumber 133 Cucumber culture in greenhouses 136 Cucumber culture in winter greenhouses 141 Cucumber culture in spring plastic greenhouses 148 Combination of heated and open soil 158 Cultivars and hybrids of cucumbers 159 Method for obtaining early cucumbers from late May to early June 161 Supports for cucumbers 164

5) 79 7 Method for obtaining early cucumbers from mid-May 164 Method for obtaining cucumbers 10 — 15 days earlier than usual еее ниеенньсние + 165 Complex of practices for protection of cucumbers against downy mildew....166 Salting cucumbers еее нуниннннннные + 170 Tomato crop неее ее неньниь 171 Biological and morphological characteristics of the tomato.173 Growing tomatoes in greenhouses 175 Tomato crop in winter greenhouses 178 Tomato crop in plastic greenhouses 183 Personal experience of growing tomatoes and cucumbers in a greenhouse on a summer cottage plot еее, 192 Specifics of growing tomatoes under plastic covers ее нннне, + 194 Methods of controlling late blight нь нь.,201 Treatment of tomatoes with fungicides 203 Recipes for preserving and processing tomatoes 207 Pepper crop еее ен етнниетиньь, +208 Biological and morphological characteristics of pepper.....209 Pepper crop in greenhouses зе еееннььние + +210 Specifics of growing peppers under plastic covers ее еьннь 214 Pepper crop in open soil 214 Diseases and pests of pepper ен, 223 Recipes for preserving peppers ее ееньеник и +225 Eggplant crop еее еечнньинь +227 Biological characteristics of eggplant 229 Eggplant crop in greenhouses ьнььнь.,230 Specifics of growing eggplant in hotbeds 233 Recipes for dishes and preserves from eggplant 235 Watermelon watermelon and melon crop еее еенинььь + +236 Biological characteristics of watermelon and melon 239 Cultivars of watermelon and melon ен кененньнье +:240 Watermelon and melon crop in plastic greenhouses 245 Watermelon and melon crop under plastic covers 249 Specifics of growing watermelon and melon under frameless plastic covers 254 System of operation of cultivation facilities (crop rotations нае ьннннн а. 256 Crop rotations in vegetable greenhouses 256