Agricultural techniques for shaping rose bushes to increase yield in a greenhouse

• Shoot length of vigorous cultivars — 90–120 cm
• Shoot length of weak-growing cultivars — 60–70 cm
• Stump height when cutting at the base — 1–1.5 cm
• Temperature for delaying flowering in autumn — 12–14 °C
• Temperature at the end of flowering — 15 °C

New renewal shoots are pruned to the height of existing skeletal branches as they grow. If there are few skeletal branches, they are shortened above the 3rd–4th or 5th–7th leaf, counting from the bottom. This technique stimulates the growth of two or three second-order shoots, which subsequently serve as skeletal ones. All subsequent orders of branches are used directly for harvesting.

The cutting height is chosen based on market needs. Cutting at the very base of the shoot, leaving a short stump, stimulates the formation of strong, long new shoots and large buds. With the second method, the cut is made above the 1st–3rd compound leaf (five- or seven-leaflet leaf) with well-developed buds. This allows for a greater number of flowers, but the shoots themselves will be shorter and the buds smaller.

Bending stems helps to increase productivity and improve bush health. This technique eliminates apical dominance, stimulates the development of large shoots from lower buds, and activates photosynthesis by preserving leaves. Bending is carried out under good lighting, heating, and regular top dressing during the spring-summer period and early autumn.

The bending technique is simple: apply gentle pressure to the shoot with your thumb, bending it over your index finger in the desired direction. You must work with gloves or using special tools. The top of the bent shoot must be below the bend point.

Pinching and autumn forcing of roses

Pinching helps to adjust harvest volumes and compensate for the August yield decline in early autumn. The apical part of the shoot is pinched above the 2nd–3rd upper five-leaflet leaf. After this, the lateral buds quickly start growing. Usually, one pinched shoot provides two high-quality flowers for harvest in September–October.

To increase rose yield in the autumn and pre-winter periods, a forcing method with over-flowering and leveling pruning is used. During the summer months, foliage mass and a reserve of nutrients accumulate in the bushes. This allows for a plentiful and high-quality harvest by the end of the year. Autumn harvesting yields high profits and fully compensates for summer losses.

1. Free flowering: from the beginning of July to the beginning of August, let the bushes bloom and completely stop harvesting to accumulate nutrients.
2. Leveling pruning: shorten the shoots formed after flowering by approximately 1/3 of their length above a well-developed five- or seven-leaflet bud.
3. Temperature reduction: during a warm autumn, lower the temperature in the greenhouse to 12–14 °C to delay flowering in September.
4. Cycle completion: after the start of the last flowering (December 10–20), reduce the temperature to 15 °C to maintain stem firmness, and after harvesting is finished, provide the roses with a rest period.

Growing regimes: from planting to harvest

When establishing a greenhouse with oculants, the agronomist's main task is to ensure high-quality rooting of the nursery plants. To do this, it is necessary to maintain the soil temperature strictly within 9–10 °C at the initial stage. As soon as the buds start growing, the substrate temperature is increased to 16 °C to stimulate shoot development. Subsequently, the bush is formed through successive pinching and bud removal.

• Soil temperature for oculant rooting — 9–10 °C
• Soil temperature during shoot growth — 16 °C
• Minimum soil temperature for winter grafting — 16 °C
• Air temperature for winter grafting — 18 °C
• Bud diameter for the first pinching — 3 mm
• Water temperature for harvest storage — 2–5 °C

Winter grafting requires a different temperature regime, as they are in an active growing season from the moment of planting. Here, it is important not to allow the root system to cool below 16 °C, and to keep the air temperature at 18 °C. The shoot pinching technique for grafts is similar to working with oculants.

1. Pinch the shoot when the bud reaches a diameter of 3 mm.
2. Wait for the appearance of second-order shoots and the growth of buds to 10 mm.
3. Remove the buds and bend the shoot, if required by the technology.
4. Remove growth points to stimulate the development of strong skeletal shoots (water shoots).

Harvesting is carried out taking into account seasonality and the flower opening phase. In summer, roses are cut at the semi-opened bud stage twice a day; in winter, one cutting is sufficient. Afterward, the flowers are immediately transferred to a sorting room to be separated by commercial cultivar.

Phytosanitary control and low-volume technology

Protection of greenhouse roses is based on disease prevention and the creation of an optimal microclimate. Even before planting, the internal surfaces of the greenhouse and the soil are disinfected. For this purpose, a 2% formalin solution is used at a rate of 1 liter per 1 m² using a sprayer, or the premises are fumigated with sulfur.

Disease development is directly linked to errors in irrigation, nutrition, and ventilation. Powdery mildew and downy mildew develop under high nighttime air humidity, so greenhouses are ventilated and heated for 15 minutes 4 times a night. Gray mold affects bushes when condensation accumulates on leaves and nitrogen is in excess. Black spot occurs due to waterlogging of the soil against a background of potassium and phosphorus deficiency, while chlorosis occurs when there is a lack of iron, which is replenished with fertilizers in chelated form.

Rose pests are also sensitive to the greenhouse microclimate. The spider mite stops developing with regular spraying of the plants and the creation of artificial fog. Thrip activity drops sharply if the temperature in the greenhouse falls below 8 °C. In modern operations, priority is given to biological control methods for pest management.

Low-volume cultivation technology for roses allows for significant resource savings and consistently high quality of cut flowers. Plants are planted in polyethylene trays 35 or 40 cm wide and 17–20 cm high, polyethylene sleeves, or 10–12 liter buckets (2 plants per bucket). Two rows of roses are placed on one linear meter of a tray containing 60 or 68 liters of substrate.

• The substrate (agroperlite with a fraction of 2–5 mm, a mixture of perlite with peat or coconut fiber) is used for 5–6 years.
• Only 5–6 liters of substrate are consumed per plant with multiple drip applications of a nutrient solution.
• Trays and buckets are installed on stands 70–80 cm high from the ground, which frees up space under the trays for heating pipes and bent shoots.
• With a distance of 1.2 m between the centers of the trays, the planting density is 80,000 plants per 1 hectare.
• The microclimate is regulated using aluminized curtains (for shading in summer and heat retention in winter) and evaporative cooling systems (fog, wet pads).

4) manual and automated irrigation and fertilization with strict adherence to the main parameters of the nutrient solution concentration;

5) carbon dioxide top dressing, which increases yield and quality by 30%;

— use of new technology in specific rose rootstocks, which ensure 5–6 years of use without a decrease in productivity, for example, Supercanina. Rootstocks are often grown from meristematic plants. Along with grafted roses, own-root roses are used. The main thing is that the cultivars are characterized by high cutting quality, good transportability, and the flowers stay in water for 12–14 days;

1) special attention should be paid to the presence of a large active assimilatory apparatus and a well-developed root system;

2) carry out timely pruning of roses, shoot bending, and flower cutting in order to optimally load the plant with commercial shoots. The correct ratio of commercial shoots and active leaf apparatus is maintained by bending a portion of the shoots.

Low-volume rose cultivation technology is a huge breakthrough that eliminates all existing disadvantages of soil-based cultivation while saving energy resources. Despite the high initial cost, the production cost of the harvest decreases in the future, and quality increases. 0 2 1 > a yy FORCING OF BULBOUS PLANTS In the winter period, when there is a particular shortage of flowers, bulbous plants, which are in great demand among the population, noticeably replenish the assortment of flowering plants. They are also attractive because the period of forcing, i.e., the time from bringing into the forcing area until flowering, is relatively short. Therefore, it is possible to have several forcing cycles per unit area during the winter. In addition, the flowers of tulips, daffodils, hyacinths, and crocuses grown in rooms, greenhouses, and orangeries are not at all inferior in their decorative qualities to flowers grown in open ground. Hyacinths and daffodils fully retain their fragrance. Forcing of tulips Currently, tulips occupy one of the top places among forcing plants. This is the most economically profitable crop. These plants are relatively undemanding regarding light, which is very important for winter cultivation. Forcing of tulips has been practiced for over two centuries. It makes it possible to obtain up to 200 or more flowers from 1 m² of useful area and to achieve mass flowering by a strictly defined date. The forcing of tulips has become popular not only in greenhouses but also in residential premises. Certain cultivars make it possible to obtain very early flowering in December, early in January, mid-season in February–March, and late in April. ® Cultivars for forcing There is a multitude of tulip cultivars suitable for forcing. Companies involved in industrial forcing purchase high-quality bulbs of exquisite cultivars from specific suppliers in Holland. < 2 \ 303 RAM =>

For early forcing, the following cultivars are used: Abba, Monte Carlo, Christmas Marvel, Golden Apeldoorn, Primavera, Zorro, Dow Jones, Mosella, Pink Impression, Jan van Nes, Gander Rhapsody, etc.

For cut flowers by March 8th: Ad Rem, Barcelona, Carola, Charmer, Cheers, Dow Jones, Golden Apeldoorn, Hamilton, Monte Carlo, Princess Victoria, Tosca, Sevilla, etc.

It is generally believed that the easiest and most convenient groups to work with are Darwin hybrids and Triumph. Their flowering rate can reach 97%. Exclusive cultivars show a lower flowering rate of bulbs. Fashionable novelties require good lighting during forcing.

There are two main growing technologies for tulips: the traditional method — which is quite simple and less labor-intensive — and the Dutch method, which ensures mass flowering by a strictly defined date, but requires precise adherence to temperature regimes.

The success of forcing largely depends on how the bulbs were grown. For winter flowering, only strong and healthy bulbs should be used, as the development of the flower in winter occurs almost entirely at the expense of organic substances accumulated in the storage scales of the bulb. Consequently, plants must be prepared for forcing while still growing in open soil. When growing bulbs for forcing, the presence of sufficient nitrogen, magnesium, and calcium in the soil is mandatory. A lack of nitrogen leads to small winter flowers with weak stems, while a lack of magnesium and calcium leads to toppling (wilting of the flower stem). To improve the quality of the bulbs, it is recommended to perform decapitation (removal of flowers). It is best to do this on the 2nd or 3rd day of flowering. It is undesirable to remove unopened buds — this can lead to the cessation of leaf growth and, consequently, a decrease in the accumulation of substances necessary for further flowering.

Tulip bulbs are lifted from the soil when the upper leaves wither and the lower ones turn yellow. At this time, the outer scales 0 sc

A YAAN, of the bulbs begin to acquire a brown color (late June — early July). It is recommended to use rounded bulbs with a diameter of at least 3.5 cm for forcing. Rounded bulbs with a diameter of 3.2 cm produce slightly smaller flowers and are suitable for growing at lower temperatures (10–12 °C). Flat bulbs are unsuitable for forcing. Immediately after harvesting, it is advisable to transfer the selected bulbs to a room with a regulated temperature and humidity regime.

Currently, the practice of selling bulbs already prepared for forcing is widespread.

Preparing bulbs for forcing: developmental stages and temperature regime

During the storage period, complex processes of organogenesis and the accumulation of biologically active substances take place in the lifted bulbs. First, leaf primordia are laid down, then the flower, and the process concludes with the formation of the pistil with tubercles. This moment is called stage C — it is precisely after this that cooling of the bulbs can begin, without which tulips in a greenhouse will not flower. An agronomist must monitor the progression of all stages of the plants' internal development.

Developmental stage	Approximate timing and morphological signs
1. Development of leaf primordia	Late May — early June
2. Initiation of the flower bud	Second half of June (leaf primordia development completes)
3. Period P1	Formation of the first whorl of perianth segments (3 outer)
4. Period P2	Formation of the second whorl of perianth segments (3 inner)
5. Period A1	Formation of the first whorl of stamens (3 outer)
6. Period A2	Formation of the second whorl of stamens (3 inner)
7. Stage C (final)	Formation of the pistil; flower primordia are fully formed and clearly visible

For the proper formation of the flower bud after harvesting, it is necessary to strictly observe the temperature regime. For forcing by March 8th, it is recommended to store bulbs at 17 °C. For early and mid-season forcing under controlled conditions, the planting material is kept at 17–20 °C until stage C is reached.

The bud initiation period can be shortened through temperature exposure. If the bulbs are stored at 33–34 °C for the first week immediately after harvesting, and then switched to the standard 17–20 °C regime, flower formation will conclude faster. After passing stage C, the bulbs are kept for 10–15 days at 17 °C, after which cooling begins.

• Optimal air humidity — 70–75 %
• Base period for bud initiation — 40–60 days
• Warming temperature in the first week — 33–34 °C
• Reduction of the flower formation period — 14–15 days
• Storage temperature after stage C — 17 °C

Cooling, planting, and forcing regimes

Exposure to low temperatures is necessary for the accumulation of gibberellin in the bulbs — a hormone that regulates the growth of the flower-bearing shoot. In programmed cooling (Dutch technology), refrigeration chambers are used for all forcing periods. In the traditional method, which is suitable for mid-season and late-season dates, bulbs planted in crates are moved to cold rooms.

When forcing small batches without automated climate systems, planting is carried out in autumn, guided by the natural drop in temperatures. Work begins when the air temperature in the rooting area drops to 10–12 °C.

1. Soak selected bulbs in a pink solution of potassium permanganate for 20–30 minutes for disinfection.
2. Prepare crates with supporting legs — these will ensure uniform ventilation and cooling. Pour a 5 cm layer of clean river sand onto the bottom.
3. Pack the bulbs tightly into the crate, pressing them slightly into the sand by their basal plate, cover with sand on top, and moisten.
4. Place the crates in a trench 30–40 cm deep, a cold hotbed, or a cellar, ensuring that the soil does not dry out.
5. As frosts begin, provide additional insulation for the plantings.

Any water-retentive and breathable substrate, free from pests and diseases, is suitable for planting the bulbs. You can use clean river sand, peat, sawdust, shredded tree bark, or perlite.

Plants are ready for transfer to the greenhouse when the shoots reach a length of 7–9 cm and a bud can be clearly felt at the base of the shoot above the bulb. Typically, crates are brought into a bright room 20–25 days before the desired flowering date. If the forcing time has arrived but the shoots are short (only 3–4 cm), the crates are shaded with black plastic film during daylight hours after being placed in the greenhouse until the shoots stretch to 10–11 cm.

Forcing stage	Temperature regime	Agrotechnical significance
First 2–3 days	12–14 °C	Plant adaptation, greening of sprouts
Active growth period	17–18 °C	Main forcing regime (flowering in 2–3 weeks)
Forcing growth rates	30–32 °C (spraying)	Spraying with warm water 2–3 times a day until leaves unfold
Delaying flowering	Temperature decrease by 2–3 °C	Inhibiting bud opening for early dates
Start of flowering	12 °C	Strengthening peduncles, extending flowering, enhancing color

Tulips must be cut strictly at the semi-colored bud phase — in this state, they easily withstand transport without damage. To maintain the commercial appearance of the flowers, dry or wet storage methods are used. In the dry method, the cut flowers are wrapped tightly in paper, placed in crates, and kept at a temperature of 1–2 °C for 10–15 days.

Before sale, dry flowers must be rehydrated by placing them in cold water for 24 hours. In the wet method, tulips are stored directly in water at a temperature of 0–2 °C. Only dark rooms are suitable for this, as buds open rapidly in light.

Programmed forcing technologies: 9-degree and 5-degree regimes

In mass tulip production, it is advisable to use controlled forcing technology for early and mid-season dates. It allows for harvesting on precisely scheduled dates. In practice, 9-degree and 5-degree temperature regimes for bulb cooling are used, which can be combined.

The duration of cooling depends on the cultivar and group of tulips. For most cultivars of the Darwin Hybrid class (Diplomat, Gudoshnik, London, Oxford, etc.), 9-degree cooling lasts 22 weeks, while 5-degree cooling lasts 12 weeks. Tulips of other groups require a cooling period that is 3–4 weeks shorter.

• Air humidity for 9-degree technology — 90%
• Air humidity for 5-degree technology — 80–85%
• Planting depth in ridges — 6–7 cm
• Planting density in ridges — 200–300 pcs/m²

With 9-degree technology, after reaching stage S, bulbs for early forcing are stored at 9 °C until October 1–5, and for late forcing — until mid- or late October. Then, planting material is densely planted into standard crates filled with substrate, equipped with supporting legs for stacking, at 60–80 bulbs per crate. Crates are stacked in a refrigeration chamber and the substrate is moistened 2–3 times a month. To maintain high air humidity, the walls and floors of the chambers are sprayed with water daily.

Shoots ready for forcing should reach a length of 7–9 cm. If they stretch earlier than planned, the temperature in the chamber is lowered to 0–2 °C. 3–4 weeks before the expected flowering, the crates are moved to a greenhouse. The optimal temperature in the greenhouse (18 °C) can be lowered to 10–12 °C if necessary to delay flowering.

Under the 5-degree technology, bulbs are stored in bulk in crates in refrigerators after reaching stage C. Monte Carlo and Golden Apeldoorn cultivars are placed in the greenhouse as densely as possible. For Darwin hybrids and Fringed cultivars, the top layer of soil is removed and the bulbs are planted according to 10x7 cm or 10x10 cm spacing schemes, while for other groups, a 7x7 cm scheme is used.

1. Preparation and planting: chilled bulbs are disinfected and planted in beds at a depth of 6–7 cm.
2. Rooting: during the first 3–4 weeks, the soil temperature is maintained at 10–11 °С and the air temperature at 11–13 °С, using cold water or snow for cooling.
3. Stimulation: 3–4 weeks after planting, the soil and air temperatures are increased by 3–4 °С.

The period from planting to flowering in 5-degree forcing depends on the timing. Early forcing requires 7–8 weeks, while mid-season and late forcing require 6–7 weeks. If the bulb planting time is delayed, the temperature in the cooling chamber is reduced to 0–2 °С at relative humidity of the air 80–85%.