Gerbera & Roses growing article November 2008

Cocopeat discs;

Over the last few years gerbera growers have been using gerbera cocopeat discs with reasonable success. I have the feeling that most growers bought the discs because they thought that it was the easiest way to fill the pots. I think that you could grow good gerberas on the cocopeat disks but you need to prepare them well.

A few disadvantage of the gerbera cocopeat disks;

1-       It requires more labour to loosen up the cocopeat, it’s important to avoid hard layers in the cocopeat and get the right air porosity.

2-       The price is higher than loose cocopeat (but you could save on transport cost).

3-       You have to find the right size which fits well in the pot.

Note; the best gerberas I see by growers, are the growers who have a cocopeat mix which keeps an open structure after the first or second year. This could be achieved by taking out the very fine cocopeat or add perlite to the mix.

Fungus gnats / Sciarid flies

Glasshouse sciarid flies are small (3-5 mm) long dark flies and they are particularly seen in a warm and humid environment in the proximity of plants. After mating, the female fly lays 50-200 eggs, which hatch in 2-3 days. The emerging larvae develop over 2-3 weeks. By that time, they are about 5 mm long, translucent white in colour with a distinctive black head.

The larvae do not only feed on decaying organic material such as algae and mould, but also on living plant material. The larvae pierce into the roots / crown of the gerbera plants, as a result of this, secondary plant diseases such as Pythium and Phytophthora, etc can be spread.

To kill the flies the best thing to do is using an LVM with a chemical against flies, for the larvae you should drench in the heart of the plants (the larvae are mostly just under the crown of the gerbera plant) and could use Bacillus Thur. var. Kurstaki or a larvicide. Be careful using harsh chemicals or oil based products because this could harm young gerbera plant.

Hypoaspis (predatory mites) can be used, but only as a preventative measure. If you have already many fungus gnats, it will take too long before they build up a good population to reduce the number of larvae.

Gerbera pots;

Because a pot supplier discontinued a popular pot used by gerbera growers, I had a few calls about what is a good gerbera pot. I find it very important to have enough holes in the bottom of the pot to have good drainage and also a flat bottom with no ribs on the side or bottom which could damage the roots.

New planting;

At this time of the year many growers have planted new plants, I would like to advice to look after the new plants because at this time of the year everybody is busy and sometimes don’t take enough care of the new plants.

1. Check if all the drippers give the right amount of water.
    

2. Drench with a fungicide after planting to protect the plant from diseases.
    

3. Take out the weeds.
    

4. Remove the first flower buds by the gerbera plants if you don’t have enough foliage on the plants.
    

5. Keep an eye on the thrips population because you don’t see the damage until the flower opens.

**Although we trust that this information could be of considerable help to the success of the crop, we cannot accept any liability for the results of your crop. All the information in this growing newsletter is without committing ourselves.

This article is written by Job Roskam of Roskam Young Plants Pty Ltd. and also published in the Australian flower industry magazine.