How to grow Supreme Callas:

The cultivation of Zantedeschia/Callas in pots requires special attention about the media, water / irrigation and the greenhouse environment, as well as a program to prevent mould. The following instructions must be carried out very carefully.

Tubers:

You can get Supreme Calla tubers delivered in two ways. Either tubers ready for planting, so with shoots already on the tuber, or stored tubers that must be received and stored at 9°C ( 48 F. ) with a relative humidity level of about 70%-80%. Always avoid a lower storage temperature as this will have a negative influence for the flower amount . If tubers are stored first and you want to plant them you have to put them at about 18°C ( 65 F. )and preferable at 80%-90% RH until the shoots start emerging. If the tubers have not been treated with GA-3 you have to arrange this as follows.

Commercial name:	Active ingredient:	Solution:
Captan	Captan (500 g/l)	1%
Shirlan	Fluazinam (500 g/l)	0,25%
Top-sin	Thiofanaat-methyl (500 g/l)	0,4%
Previcur	Propamocarb-hydrochloride (722 g/l)	1%
Berelex (GA-3)	Giberellic Acid (9,6%)	1 tablet to 6 litres

We advise you to buy tubers prepared and ready for planting. Check your local supplier at the where to buy page.

Media to use in the pots:

The media should be well draining with a pH value of 6,5.

We recommend to use a media based on a high percentage of Coco peat (70%-90%).

Avoid fine particles in the media as this can will result in too wet pots.

Pot size and tubers size:

In order to produce good quality pot plants we recommend the following tubers, pot sizes and plant densities.

Pot size	In cc	Plant density netto m2	Tuber size 12/14 14/16 16/18 18/20 20/24
9 cm	285 cc	35	X
11 cm	520 cc	30	X X
12 cm	> 620 cc	30	X X
14 cm	> 1.000 cc	25	X X
17 cm	> 2.000 cc	20	X X
19 cm	> 3.000 cc	15	X X

Planting:

Tubers must be planted with the shoots facing upwards and with at least 2,5 cm / 1 Inch potting compost above the tuber.

Greenhouse temperatures:

After planting the pots can be placed directly in the greenhouse or in the store until the shoots are coming out of the soil. The best temperature to start is between 16°C - 20°C (60 F. - 68 F.). Avoid desiccation of the upper soil level after planting.

Commonly moisture of the soil followed by watering with a mould resistant agent, be careful with watering until the shoots are showing.

Stage:	Temperature:
From planting until shoots of 3-5 cm	16°C - 20°C (60 F. - 68 F.)
From 6 cm until you see the flowers (day)	16°C - 24 °C ( 60-75 F. ) during the day
From 6 cm until you see the flowers (night)	13°C - 16 °C ( 55-60 F. ) at night
From flower colouring until delivery (day)	16°C - 24 °C ( 60-75 F. ) during the day
From flower colouring until delivery (night)	13°C - 16 °C ( 55-60 F. ) at night

Higher temperatures during the growing will reduce the cultivation time but especially under low light will lead to a weaker and longer plant.

High light intensity is required for the best flower colouring and to avoid extended growth of the flower stem. Too much shade or low light intensity can cause a lower number of flowers and less intense colours.

A temperature between 10°C - 13 °C ( 48-55 F. )can be useful in delivery stage for holding the crop for ship date.

Horizontal air circulation, usually from vents hung in serial order in the greenhouse, is important for an equable temperature/climate.

A moderate till high humidity level of between 65 and 75% is best. Try to prevent a lower humidity level of under 50% and avoid heavy RH changes during the day. Shading methods can be used to avoid low RH rates and too high temperatures.

Watering:

Watering of the callas can be done with overhead sprinklers. Be sure that your sprinkler system is in optimal condition. Every dry spot can give problems for the plants.

After planting you have to water 1 or 2 times to let the plant start shooting. The mould resistant agent should be sprayed after the soil has been watered for the first time. Moderate watering is required until the leaves unfold. The pots should not be constantly wet, rather slightly dry.

Constant water management is a crucial aspect of growing Callas in pots.

If root decease is found, (this looks like bare, glassy or brown roots), remove the effected pots,and decrease the moisture of the soil slightly. Roots should be checked regularly by taking some plants out of the pot. Look very good to the weather forecast to decide how many water you give the plants. Watering can be done best in the morning when you have the lower temperature of the day.

Good quality water raised to an E.C. of about 1.5 (managed through a fertiliser program) stimulates growth and health. Avoid high levels of Na, SO4, HC03 and Cl. as this might have a negative influence for the plants. Be sure that the E.C. in the pots will not raise higher than 2.0.

Fertilization:

Approximately 800 gram NPK ( 12-10-28) per m3 is usually mixed through the compost as a basic fertilizer program. It's important to have sufficient levels of iron and magnesium. It's highly recommended to apply fertilisers during the crop.

Keep in mind that a proper balance between Nitrogen and Potassium is the most important aspect in order to avoid extensive plant and foliage growth . A improper balance ( For instance to much Nitrogen ) results usually in a taller and softer plant shape .

Growth regulation:

Bonzi (paclobutrazol) has proved to be the most effective growth and height regulator for Callas in pot.

The length of the plants depend on the temperatures, light, moist of the soil and variety.

The normal recommendations, can diver considerably by other locations. You can use them as a base to start a Bonzi programme.

The first application of the agent must be made when the shoots are 5-10 cm. (2-4 Inch) tall.

The best time to apply Bonzi is through a drench within ½ to 2 days after watering and applying the mould resistant agent, this way you can be sure that the pots are evenly moist. Because the length of the shoots can verify per pot, we recommend that the pots are kept separate or are marked.

Advice: 1 cc Bonzi (4 gram /liter paclobutrazol)in a drench of about 50 cc water per pot.

For the specific advise per variety see the specification summary that is attached to the variety.

You can do an extra treatment if preferred. This is only necessary if the plants are becoming too tall. The decision to continue this treatment depends on your climate and growth situation.

The plants must be actively growing for Bonzi to be taken up by the roots and assimilated.

Be meticulous and experimental. Keep a record of plants not treated with the solution so that a comparison can be made between the two methods.

Bonzi is very persistent in the soil. Be careful with the use of Bonzi for the following crops.

Crop protection:

Erwinia Carotovora, in combination with Pythium and Rhizoctonia, usually caused by too little or too much water, are the most common diseases and can have a negative influence for the final result of the crop.

A well drained medium and a preventive mould-resistant program are of essential importance.

Growing healthy plants begins with a good environment, temperature, water, fertilizer administration, choice of agent, and sanitary measures and the preliminary treatment of the tubers.

If you see leaves falling down you can apply a fungicide against Rhizoctonia like Amistar (azoxystrobine 250 gram/liter).

Keep an eye on the pots before growth by taking the tubers / plants out of the pots and check the roots regularly, start in week 2 or 3. Inspect them carefully for bare spots or browning / glassy roots to establish the need to apply pesticides.

If you notice problems with the roots you can apply Alliete or Ridomil gold. A preventive treatment with these fungicides can be useful.

Keep an eye out for plants infected with Erwinia. Remove them directly and destroy them.

Insects:

It is important to control insects in order to avoid quality issues.

Check for white fly, aphids and thrips and treat when necessary.

For more information you can always contact us by e-mail.

Risk policy

These instructions are not a prescription or guarantee, nor recommendations or endorsements of chemicals mentioned.