Zantedeschia / Calla Growing Instructions
Receipt and inspection of tubers
Check the tubers for:
• Proper tuber size
• Proper quantity
• Inner quality
• Presence of main shoot
Use a mix that drains well with a high level of peat and perlite added. Sunshine mixes generally work well.
Zantedeschias can grow without too much fertilizer. High levels of Nitrogen can increase the foliage production but will make the plant also softer. This can reduce flower production, increase the risk of damage from Erwinia, and delay the development of the new tuber. Iron and Boron are two other elements that are extremely important in the development. Before planting, have soil samples taken that will also be tested for micro elements.
A basic application of fertilizer previous to planting is preferred.
Advice based on sample testing conducted by the Laboratory for Soil and Crop Testing (BLGG) in Naaldwijk:
• pH: 6 - 7
• EC: 0.7
• N : 1,5
• P : 0.20
• K : 1.5
• Mg: 1.5
• Ca: 1.8
• Fe: 10-15
• B: 30
• HCO3: < 0.3
Later on in the crop we recommend to keep EC Level at about 1.1 to 1.3 EC.
Planting the tubers
When you receive the tubers keep them at room temperature. Do not put in a cold cooler! Plant the tubers within a few days of receiving. Do not plant the tubers too deep. About 1.5 inches of soil on top of the tuber is more than enough. Plant the tubers with the sprouts/ shoots up. Be careful with planting so that tubers do not get damaged in the process. A drench is done with fungicide after the first irrigation, so approx 2 weeks after planting.
Bonzi (Paclobutrazol) is most common used in Callas to keep them shorter. The rate varies a lot between different varieties. Also time of the year and the age of the tuber should be taken in consideration to determine the rate. Rates vary from 5 ppm to as high as 20 ppm. The first application is given when the sprouts are 1 to 2 inches tall. During the crop sprays are common or sprenches. A variety however that needs Bonzi in a February planting at times do not need any application at all if you plant them in July, therefore test out the rate first for best results.
Zantedeschias can be grown on the dry side. After planting wait 4 to 6 days to water. This is very important! Make sure to plant in a fairly dry soil. After 6 days, give the pots a good watering. Callas will make thick white roots and will root throughout the pots. Irrigate early in the morning. Water when the mix is starting to dry out not before that since keeping the medium too moist will cause glassy roots.
After planting you want to keep the greenhouse on the warmer side (62° to 68°F) this will enhance emerging of the tubers. After emerging of the tubers keep the greenhouse cooler at around 58°F to 60°F. Try to keep the humidity at about 80%. This can be done by a cracked vent and air circulation (fans). During the day keep venting so that the humidity will be around 60 to 65%.
After emerging do a drench with a fungicide. Cleary's mixed with another fungicide often works well. Keep an eye open for aphids. They can nestle themselves in between shoots and therefore sometimes hard to detect. Marathon has a good long term working solution and can be applied after pair of leaves is visible. In the fall you can have a chance of botrytis in the flower. It can happen in a few days' time so be aware. You will see small brown spots (circles)
Every 3 to 4 days Callas are being harvested. Try to do this during the early mornings before it starts to get warm. Be sure the pots are moist when harvested since they often do not get water for a while in the store.
Flamingo Holland cannot be liable for any loss of profit, growing result or any other commercial damages resulting from use of this guide. This guide is for information purposes only and are not warranted for content, accuracy, or performance overall.