Gerbera & Roses growing article February 2009

Cost cuttings;

With current economic conditions growers ask me how they could make cost cuttings; I tell them that they have to be really careful with this. Overall growers already know that most of the costs are necessary and trying to save an extra dollar can cost a tenfold of the preferred savings.

A few examples how not to save money;

1-       Growers changing from mains water to dam / river water but they don’t adjust the filtration which could cause blocked drippers or don’t adjust the amount of acid used to control the PH. Make sure that you use good filtration and adjust the PH. Also take a sample of the new water source to know which elements are already in the water so you could adjust this in the A or B fertilizer tank.

2-       I visited a grower and saw a more yellow leaves in his crop, he told me that he give every second day water with fertilizer and the other day only water (no PH control on this water). In summer you could maybe get away with it for a short time because of the high transpiration, but in autumn / winter it will create a weaker crop which is more susceptible for diseases. 

3-       Try to use less chemicals or spray less, this could result in extra cost when the insects or diseases get out of control. (a better way is to use cheaper chemicals which kill a wide range of insects, works well if you use a LVM )

4-       With cheaper cocopeat you have a higher chance that less chips are used and this could result in a wetter media and cause less growth or more diseases. If you divide the cost over the years you use the growing media also the cost per pot or growing bag are not that high.

5-       Don’t use less post harvest preservatives because the quality of your product must be as good as possible, complaining customers about the quality of your product is the last thing you want.

 Note; Of course every grower is thinking about the increasing cost, but before you make any changes think about what the consequences could be and check after the changes if things are going as expected.

Black petals in red roses;

I had a few growers who had trouble with black petals in red roses; see below a few suggestions what the reason could be;

1-       The plastic – red roses require UV blocking plastic.

2-       Always use diffused plastic on roses and not clear plastic.

3-       Too low temperatures, especially at night (the ideal night time minimum is at least 16 degrees) or a too large temperature difference between day and night.

4-       Fertilizer imbalance, especially trace elements.

5-       Some varieties are more sensitive for the black petals than others so trial a new variety under you conditions before you plant large quantities.

Herbicide damage;

In the past few years I have visited a few growers whom had severe damage on their crops due to herbicide, I would advise every grower to take care of the following things to avoid these problems;

1-       Never use herbicide in a spray tank you use for your normal spraying, even after a good rinse there is a chance of damage.

2-       Ask your supplier which herbicide you could use for weed control in the greenhouse, Round-up is not a chemical you can use in a greenhouse!

3-       Always start with an empty spray tank; the best thing to do is to rinse the spray tank before you make a new one ready so old chemicals can’t cause a risk.

4-       Keep you herbicide chemicals stored away from the normal chemicals / fungicides, and make sure that only qualified persons have access to the herbicides.

5-       Lock the room where your spraying equipment is stored.

6-       There have been a few cases that sabotage was the reason of the damage by herbicide, so make sure your property is secure. 

Note; When you have damage, find out which herbicide caused the problem. There are a few labs in Holland which can identify which herbicide is used by testing leaves of the plant.

**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.