|
Practical Principles for Gerbera Culture in Soil
1. Growing Media
2. Soil Preparation
3. Fumigation
4. Soil Beds
5. Planting
6. Irrigation
7. Tensiometers – manual or electronic
8. Fertigation
9. Greenhouse Management
10. Heating
11. CO2 Enrichment
12. Plant Protection
13. General Sanitary Conditions
Principles for Growing Gerberas in Soil-less Media in Mediterranean and Subtropical Climates
14. Growth Media
15. Ideal volume for the gerbera roots’ system
16. Micro-Irrigation
I. Amount of Water
II. Timing of Irrigation
17. AutoAgronom Irrigation system
18. Fertigation
I. Feeding Formula*
II. Acidifying
III. Electrical Conductivity (E.C.)
© Gerbera Breeding Ltd.
Here are some of the recommended principles for successful gerbera culture. These principles, if kept by the grower, with adaptable accuracy, will enable him to save in the following input factors: water, fertilizers, fuel, electricity, chemicals (fungicides and insecticides), work, etc. And yet having well established plants with high flower production of high quality, means: strong stems, shining flowers and resistance to common greenhouse diseases and to the environmental conditions.
Natural deep drained sandy / light soils.
- Rotating the upper layer of the soil with the plants remainders (leaves and roots).
- Router ploughing up to 60 cm. for opening the bottom layer of the soil.
- Shovel ploughing for leveling the growing layer.
- Heated Methyl-Bromide 50 kg / 1000 M2. (Forbidden according to international agreements from 2001 on)
- Steaming or solar energy method.
Raised beds 30-60 cm above pathways made of present well prepared soil. Narrow beds (35cm on top of the bed) for one row culture or wider beds (70cm on top of the bed) for two row culture (15~40~15).
Plant on soil surface (never plant gerberas deeper). Plant only healthy plants.
- Use dripping systems for water supply and feeding (fertigation), and for washing the soil in the case of accumulation of salts and high E.C.
- Use only the dripping system for washing the soil. Using Sprinkles is allowed only after fumigation, and for wetting the air and the young plants for a short period after planting.
- Irrigate Daily with 4 to 6 cubic meter of water per 1000 M2 as regular fertigation, or if using tensiometers, irrigate according to the tensiometer readings.
A Tensiometer is a device that measures the water pressure in the growing media.
- In the case of manually Tensiometer (detect units of Centibars), we use 2 tensiometers for each irrigation unit. One in a depth of 10cm and the second in the depth of 25cm. Daily inspection of the water pressure in the soil enables the grower to decide when and how much to irrigate. The use of tensiometers practically begins three months after planting when the roots’ system is well developed.
- In the case of using electronic Tensiometer (detect units of Millibars), 1 Tensiometer in a depth of 10 – 15cm is sufficient for automatic irrigation control.
There is no need to add any organic material or even basic fertilizers before planting. Feeding is based on fertilizers given through the irrigation system by appropriate pumps.
Feeding formulas and the use of different fertilizers is very flexible, depending on water quality and on soil physical character.
- Good formulas are 100 - 140 ppm N, 20 - 40 ppm P, 150 - 220 ppm K in the irrigation water. These formulas are achieved by mixing commercial fertilizers available almost in every country.
- Microelements are very important; do no forget to add them as a solution into the fertilizer tanks.
- The use of acids for lowering down the pH to 6.5 – 5.5 is a common action and it needs an extra tank and pump for it. Nitric acid is a preferable acid since its N is calculated as a part of the feeding formula, however Sulphuric acid is also a possibility.
- Soil solution test gives important information regarding salinity situation, therefore it should be done often by the grower. Handy kits for measuring the EC, pH, NO3. P, K, Ca, and Chlorines are available on the markets.
On the other hand, Soil test should be done by a known soil laboratory.
- Soil washing - in case of salinity 20-30 cubic meters of water should be given continuously per 1000 M2.
- Ventilating. Controlling the ventilating by side walls is a must. High angle windows are very useful too. This is true 24 hours during summer, and in winter when the greenhouse is not heated or enriched by CO2.
- Close walls and windows in winter only when temperature drops to the desired heating night temperature. In summer close the walls partly in dry hot weather.
Heating by air heaters is a fast system and very effective for gerberas in the Mediterranean climate. The temperature in winter nights for Shoub's varieties is 12-14 C.
CO2 enrichment is accomplished by a gas burner for 2.5-3.5 hours from sunrise up to 800 - 900 ppm.
- Use chemicals against insects only and when you see them, never do it according to a previous program. If Red mites for example exist in some spots, spray the spots' center and the surrounding plants only, and not the entire greenhouse. But against Leaf-miner or White-fly spray the whole greenhouse. Dusting with 90% Sulphur towards the lower side of the mature leaves, is very efficient against the White fly.
- Botrytis - the common greenhouse disease is controlled mostly by ventilators and by dusting with very little amount of fungicides relevant to this disease (50-30 gram / 1000 M2) once a week. Close the greenhouse for that action.
- Use a sprayer (blower type) with the smallest diffuser jet and spray above the plants. For an area of 1000 M2, you may use 5-10 litters of solution if sprayed very effectively.
Controlled irrigation and feeding results in healthy growth and slow aging of the mature leaves. These conditions cut down the need for cleaning and thinning leaves. As a result, the plants stay dry; therefore it reduces the possibility of being diseased, light is penetrating into the plants heart during the day, and so do the heated air at night. Spraying and dusting become more efficient.
If there is a need to clean the old dry leaves, never do it when the weather is wet. Brush your shoes when entering the greenhouse. It helps to avoid contamination of nematodes.
For further information please contact us by e-mail and we will assist you as much as we can.
A good growth media, for most of florist crops and ornamental plants, is any media that holds water, that amounts to about 50 - 60% of its volume, and easily and quickly drains out any water.
In this context, pure Coco peat from reliable source, is one of ideal media for many plants including gerberas, and there is no need to add or to mix it with any additives.
Volume of 4 liter media per plant is optimal for a mature gerbera plant.
Container – the ideal 4 liter container for gerberas has a diameter of 17 cm and height of 22 cm, with an a total surface area of drainage holes amounting to 3000mm2.
Micro-irrigation systems are ideal for soilless media culture. Irrigation systems that allow accurate water flow of 100 - 250 cc per hour per emitter are considered Micro-irrigation systems.
Slow water flow of 15 - 30 drops per minute (4 - 2 seconds between the drops) allows diffused water movement in the media (horizontal movement before gravity movement), and by that ensures a unifying wetting of the volume with every irrigation.
The daily amount of water per plant and the timing of the irrigations are the most important criteria for successfully grown gerberas in soilless media.
The daily advisable amount of water to be supplied per plant, is a combination of the volume of water used by the plant (transpiration) + the evaporation from the media + the drainage volume, needed to leach out the excess of salt accumulated daily in the media.
Under summer conditions of Mediterranean climate, the amount of water used daily by gerbera plant is about 600 - 800 cc. And in winter is about 300 - 450 cc.
(See the attached summary about the use of the AutoAgronom irrigation system in gerbera breeding ltd),
The ‘AutoAgronom’ (by Rotem Dan) , a new accurate irrigation system, controls the amount of water and the irrigations timing , in the most efficient accuracy practice known today. It controls the water tension in the media close to the saturation point, It irrigates 40 to 140 short irrigations (2 - 4 minutes each) during 24 hours, and at the same time controls the EC, the pH, and the Nitrates in the irrigated water as well as in the roots’ zone solution. The use of the AutoAgronom system allow us to reduce the amount of fertilizers to almost 30% of the normally advised quantities, to save about 30 – 40% of the water used for irrigation in soil-less media, and at the same time to avoid continuously any risk of salinity situation. See the new presentations regarding the AutoAgronom.
Use tank [A] for the macro and micro-elements. Use tank [B] for the acid.
Keep always the pH of the irrigated water in the range of 6.0 – 5.5.
Inject the fertilizers solution [tank A] to the irrigation lines to achieve the following formula:
N 100 - 150 ppm. P 20 - 40 ppm. K 130 - 200 ppm Ca 100 - 140 ppm.
Fe 1- 2 ppm. Mn 0.3ppm. Zn 0.3 ppm. Cu 0.05 ppm. Mo 0.05 gr. Bo 0.4 ppm
* This advised formula is not relevant when the AutoAgronom system is in use.
PH of 6.5 to 5.5 will keep the irrigation system free of clogging, and at the same time will create optimal conditions for mineral and microelements absorption by the roots.
Change the pH from 8.0 -7.0 to pH of 6.0 - 5.5 with Nitric acid, or Sulphuric acid.
Be aware that because of the roots activity, the pH of the drain water could be lower than the pH of the fertigation water.
The Fertilizers of the above suggested formula if injected to the irrigation lines contribute about 0.6 to 1.0 mS/cm above the E.C. of the water used for irrigation. Higher E.C. in the drainage (about 10-15%) proves the effectiveness of the Micro-irrigation system in leaching the excess of the salts from the total roots’ media. Lower E.C. in the drainage proves that the amount of water given is higher than needed
Note - If conventional Irrigation systems (characterized by gravity water movement) are used for soil-less media, it causes always fast drainage. The quality of this fast drainage reflects only the wetted zone in the growing container, and not the real E.C. situation of the total container’s volume. Therefore, the E.C. of the drainage might be almost as the E.C. of the fertigation water.
Dr. Yoseph Shoub
Savyonim 58, 45905
Ganey Am, Israel
Tel: +972-50-5529089
Email:gerbera1@zahav.net.il
Fax: +972-72-2555997
http://www.gerberaisrael.com
© Gerbera Breeding Ltd. |
