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General
Sow
Where to sow
Grafting
Seed harvesting
Storing seed
Labeling
Watering
Cultivation climate
Growth season
Diseases
Importing

Use rain water for watering or so called soft tap-water (max.10oDH). When using inert substrates such as lava or rock-wool is it wise to add each time when you're watering a small quantity of fertilizer. 
'With the use of tap-water it becomes necessary to lower the pH level to pH 5,5. The frequency of watering is at best between 5 and 10 days; it depends on the location of the greenhouse and the weather conditions. In any case do not water if the substrate is still moist! Check this before sunrise. Water only if the weather forecast is favorable, the plants have to be dry within a couple of hours. 


It is preferable to water in the morning, except during hot summers then the best time to water is in the evening. 
For a balanced growth a good fertilizer is required.

A fertilization method for inert substrates have been utilized for years with success now is the recipe of Hans Wortel (Neth) (See Succulenta nr. 8 and 9 of 1982) who uses two solutions A and B. The composition is as follows:

Solution A
For 20 liters:
3,2 kg Nutriflora T
50 gram FE DTPA (iron)
500 ml Nitric acid 38%

Fill a barrel with a capacity of approx. 25 liters with 20 liters tap-water add 500 ml Nitric acid, then the 3,2 kg Nutriflora T, stir firmly during 10 minutes and add the 40 gram FE DTPA . Stir again after 6 hours for 10 minutes. After 24 hours the solution becomes clear and can we transfer  it into easier handling bottles. Remove the sediment from the barrel. Stored in dark and cool place the solution can be kept for approx. 6 months.

Solution B
For 20 liters:
4 kg Nitric lime
500 ml Nitric acid 38%

Fill a barrel with a capacity of approx. 25 liters with 20 liters tap-water add 500 ml Nitric acid, then the 4 kg Nitric lime and stir firmly until the solution becomes clear, and than we can transfer  it into easier handling bottles. It is advisable  to add 3 ml A and 3 ml B for every liter of water when watering. 
When using tap-water the addition will lower the ph degree to 6 - 6,5. When using rain-water the ph degree will lower to 5. 
With rooted plants a pH of 5 is advisable. If you lack rain-water then you need to add Nitric acid to the tap-water. The reported quantity of 3 ml is the average dose during the growth season. Our experience learns that these doses needs to be adjusted according to the light quantity to obtain the best efficiency. Low light conditions - spring, autumn or a plant position with poor light 1,5 ml per liter, and high light conditions - summertime or outside - c. 5 ml per liter water.
These small quantities of nutritious salts leave no visible traces behind on the plants and water can be poured over the "head" of the plant. This is not the case when "hard" tap-water is used. The remaining chalk on the thorns and at the base of the plant can leave ugly traces. In the later case watering on the edge of the pot is wiser. The so-called ebb-and-flow-system is only advisable if the returned water can be disinfected/decontaminated, otherwise diseases and plagues spread in very short time over the entire collection.

The above mentioned compositions may also be used with the usable substrates. For convenience sake also commercial nutritious salts are available. These can also be used, provided with care, for the inert substrates.

In all cases be careful for shortages in the nutrition such as minerals and spore elements.
 

Copyright 2003

email: Piet van der Laken