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Growing Information Alstroemeria is still a relatively new product on the world market and interest in it is continually growing. This growth is due to the fact that this crop is fairly easy to cultivate and does not require special demands. The flowers are beautiful and have a very long vase life. 1. Morphology More technical related articles on alstroemeria growth are found in the ‘new archives’. Alstroemeria has an underground rhizome, which develops vertical shoots. The main rhizome can generate new lateral rhizomes that can also produce flowering shoots. Above the soil, the stems do not generate any lateral stems. Since the major part of the plant's development occurs underground, the temperature of the soil plays an important role in this development. After a period of high soil temperatures, the plant produces many shoots (and new rhizomes). However, depending on the variety, many of these shoots remain blind (i.e. they do not produce flowers). One alstroemeria stem can produce 3 to 7 flowers, each on a lateral pedicel near the tip of the stem. There are different types of alstroemeria (orchid, butterfly, and aurantiaca) but most of today's types are hybrids. Although there is year-round production, alstroemeria still have a production peak in spring and (when soil cooling is used) also often in the autumn. top 2. Culture methods and productivity Most alstroemeria are cultivated in heated glasshouses or plastic tunnels. It is also possible to grow them in unheated glasshouses, plastic tunnels or even outside as long as the soil doesn’t freeze. Note, that if temperatures are too cold (<8 oC / 46,4 oF) and too humid, they won’t flower in the winter The production level shows a wide range from 180 to 400 stems per m2 per year depending on variety, production method, the amount of light, and the availability of soil cooling. Normally about 60-80 % of the production can be sold as first quality (4 flowers or more per stem with a certain stem thickness). This depends on the variety and the year of production. For a general impression of possible production levels:
top 3. Planting 
Young alstroemeria plants are usually propagated by tissue culture, and sometimes by manual division of the plant. The plants are delivered in 9-cm or 7-cm pots. Alstroemeria are planted in two rows running along beds measuring 1.02 to 1.19 metres wide. For beds 1.02 metres wide, we normally plant 3.1 plants/m² of glasshouse space. The distance between plants along a row is 34 to 40 cm depending on the type of alstroemeria and the width of the beds. The distance between the rows should be 40 to 50 cm, depending on how fast the rhizome grows toward the edge of the bed. Two to four layers of support material (netting) are required. The netting usually has openings of 20 x 17 cm.
top In Europe, alstroemeria are usually planted from November to June and in the southern hemisphere from September to December. top Alstroemeria are being grown on practically all types of soil from peat, sandy soils to heavy clay. As long as the soil contains enough air and is properly drained, producing high yields of stems is possible. If this is not the case, then it is advisable to improve the structure of the soil by adding composted bark. The irrigation system must be adjusted to the soil. Normally, water is provided from underneath by a sprinkler system. Drip lines can also be used, but the horizontal transport of the water through the soil must be sufficient to keep all of the soil consistently moist. In hot countries, a combination of drip lines and an overhead sprinkler system can be very useful; this combination also maintains a better climate in the summer if the humidity gets lower than 50 %. Alstroemeria perform best when plants receive frequent, fairly heavy watering, because most of the roots are located in the top layer of the soil (0-25 cm beneath the surface). Only when growth is very intensive in the autumn and winter, or when the leaves turn yellow is it better to give less water for a few weeks. top Before planting, make sure that the soil has the proper structure and that the amount of phosphate in the soil is sufficient (PAL> 80). The values for other nutrients must be at least in line with those listed in the table, below. Values slightly under these levels should pose no problem provided that highly soluble fertilisers are administered on a regular basis (at least once a week) via the irrigation system. Commonly provided nutrients are ammonium nitrate, calcium nitrate, potassium nitrate, magnesium nitrate, and magnesium sulphate. In the Netherlands, most growers use the A and B container system in which they provide fertilisers with almost every watering (using water with an EC of about 1 to 2). To get plants off to a good start, the concentration of salt (the electrical conductivity or EC) should not be too high at planting time, especially in the summer (1,0 Ec). The following table provides a list of minimum and maximum nutrient levels in the soil. For reasons of quality it is better to strive for the higher levels in the autumn and winter when growth is very intensive. During periods of extreme crop evaporation (spring and summer), strive for the lower figures. mmol/l
For substrates like perlite or cocopeat there are other nutrient levels (not listed here). If the pH of the soil is too high (7 or higher), iron or manganese deficiency may occur. This will be displayed by a yellowing of the leaves. A lack of iron can be treated by providing 6-8 grams of EDDHA per m² or by providing this regularly in irrigation water, but it will not always solve the problem. Yellowing of the leaves can be a frequent problem with certain varieties. Yellowing can appear after a high production period when the plants have lost some active roots or at the end of winter, when the plant has fewer roots due to low light conditions. Cold soil (10-12°C / 50-53,6°F) and excess water prolong the problem. The butterfly types display fewer problems in this regard. top For a period of six weeks after planting, the temperature is to be kept at 13°C (55,4°F) during the night and between 14-16°C (57,2-60,8°F) during the day. A lower temperature causes a slower start in the production, but can provide higher quality and shorter stem length. During the summer, an average of 17 to 22°C (62,6-71,6°F) is an excellent temperature for the growth of alstroemeria. Cool nights and maintaining soil temperatures between 14 to 17°C (57,2-62,6°F) are desirable for high-quality results. In warm countries, it is necessary to use whitewash on the glasshouse if the temperature regularly rises above 30°C (85,9°F). During the late autumn and winter, the temperature is kept between 10 and 14°C (50 and 57,2°F), depending on the variety, its length, and the quality of the stem. The more natural and/or artificial light the crop receives, the higher the temperature that can be maintained. Temperatures under 9-10°C (48,2-50°F) lead to the very slow development of plants as well as very low production. In the early spring (February/March), it is better to heat a little more (13-15°C / 55,4-59°F) or on sunny days to keep the warmth inside the glasshouse by ventilating less. This will produce an earlier, more uniform production peak in the spring and a better recovery of the foliage before the summer. top The development of alstroemeria shoots takes place in the underground rhizomes. High soil temperatures during the summer will often lead to poor flower induction among many varieties (e.g. Eldorado, Valencia). This is why the number of blind shoots increases during the autumn and winter. There are varieties less susceptible to developing blind shoots and which also flower in the autumn without soil cooling (e.g. Napoli, Tropicana, Odessa, Bordeaux, Modena, Goa, Sacramento, Audrey, and Fuego). But even then, most become taller and produce later and less uniformly than when soil cooling is provided. In addition, the crop is prone to be more labouring intensive. Nowadays, many growers use a soil cooling system to prevent the crop from making too many blind shoots in the autumn. For most varieties, it is advisable to keep the soil temperature at about 14°C (57,2°F) in the summer (in Europe, this is from June to October). In countries where light intensity is higher (Southern Europe and Japan), this could be a little higher (15-17°C / 59-62,6°F). In countries like Colombia where alstroemeria are grown at an altitude of about 2000 meter, it is not necessary to cool the soil. Generally during the spring (before week 20), the soil temperature may be allowed to rise a little higher for a few weeks before one starts to cool the soil (up to 16-17°C / 60,8-62,6°F). This will encourage the plant to generate sufficient numbers of shoots before summer. When applying assimilation lighting with high-pressure sodium lamps (also called High Intensity Desclosure lamps = HID), the soil has to be between 14-16°C (57,2 -60,8°F) year round (see the section on Lighting). top The ideal humidity is between 70-80%. Although alstroemeria is not very susceptible to Botrytis, it is better to keep the humidity below 90% during the winter. High humidity produces taller stems as well as larger and weaker leaves. During the early spring, on the first warm days of the year, quite a few varieties are susceptible to leaf scorch. The leaves (and especially the stems that are just starting to produce leaves) have not yet adjusted to the evaporation process. To prepare the plants for such circumstances, it is better to ventilate and/or heat a bit more on the days and nights when humidity levels are higher than 85-87%. The use of fans in the glasshouse can also improve the situation. Nevertheless, it is very difficult to prevent this problem on the first sunny day following a cloudy period. On the other hand, on very sunny days during the spring, when the relative humidity drops below 70%, it would be best to use a sprinkler system or a screen. top Giving extra CO² in glasshouses will yield a better quality and a 10-20% increase in production. Maintain a CO² level of up to 350-400 p.p.m. in the summer and check that the windows are not more than 20% open. With closed windows in winter, the best CO² level is between 600-800 p.p.m. With a CO² level higher than 1000 p.p.m., the plants are neither damaged nor benefited. top Assimilation lighting with HID-lamps causes a better quality and more flowering stems in winter. Lighting with 3000-3500 lux/m2 can start towards the end of September or at least by early October with a 14-hour day length and terminating in February with a 12-hour day length. Day length is the hours of natural daylight plus the hours of assimilation lighting. Due to the restrained shoot formation caused by long days; especially in combination with low soil temperatures (14°C / 57,2°F and lower), lighting should be restricted to 12 hours from December to February. Maintaining a longer day length in combination with a low soil temperature will result in insufficient numbers of new shoots in December and January - resulting in decreased vegetation and quality in February/March. Also, the peak in production in spring will arrive later and provide smaller yields. It is recommended to count, on a weekly basis, the number of young shoots (up to 10 cm in length) of a set sample of plants. This is a simple control measure, to see if the plants are continuing to make new shoots. With more lighting capacity (4000+ Lux/m²) and higher soil temperatures, it is possible to maintain a day length of 15-18 hours from September to April, as well as glasshouse temperatures between 14-15°C (57,2-59°F). In climates comparable to Northern Europe, this can result in a production of about 50-100 more stems/m2 per year - stems that are of better quality in the winter. With 8000 lux/m² production becomes even higher and more regular. However, profitability depends on the investment needed and the costs of electricity. This has to be calculated in each situation. 12. Diseases and other problems While alstroemeria are not particularly susceptible to diseases: aphids, thrips, spider mites, slugs, caterpillars, white flies and nematodes (Pratylenchus) can at times cause problems. Only when the soil becomes too wet do Pythium and less often Phythophthora present a problem. Rhizoctonia sometimes develops under warm humid conditions. Few varieties are susceptible to viruses such as TSWV and INSV, which could then present serious problems. Weeds can be a problem in the summer, when the plants have not yet produced much foliage. The following nutrient deficiencies can develop: 13. Harvesting and other required work
Brief growing instructions for the Alstresia IntroTime to plant The course of growth Soil temperature Light Harvesting Intro Time to plant The course of growth Soil temperature For the Orange Cuba® and Yellow Cuba® is it advisable not to surpass a soil temperature of 17ºC (62,6 ºF) in the spring and in the summer to cool from 15-16ºC (59 - 60,8 ºF) so that the crop remains at a pleasant height and that it regularly produces. Do not start cooling too early in the summer (not before week 25), there must be sufficient new shoot growth visible after the peak production in the spring. If the crop is poor in the summer and that there is too little new growth out of the soil, do not cool the soil as of yet. Only when you are satisfied with the amount of new shoots visible out of the soil should you then begin with the cooling. Example of the proper progress of the soil temperature for the Orange Cuba® in the Netherlands.
Light H.I.D. lighting Harvesting For specific questions over the Alstresia in general and over the cooling and lighting methods please contact H.vd.Voorden@alstroemeria.com © 2002 Könst Alstroemeria B.V. |
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for the plant crop. This is done on a weekly basis. 
More technical, growth related articles are found in the |
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