Silicon Biostimulants benefit flower grower’s IPM strategy

Mr Marsden has been working the 14-acre farm for 23 years and has seen many products come and go. With 99 percent of the crops grown in soil and only 20 percent under poly tunnels, he faces a variety of pest, climatic and agronomic challenges.

“Our soil has a high pH of around 7.8 and, with free chalk in the soil, there is little we can do to change it, so we use compost, top dressings and, this year, we have started pumping a worm tea through the crops to add beneficial fungi and microbes,” he says, 

Among the crops are roses, herbs, scabiosa and hydrangea which are all drip irrigated and fed with a water soluble granular fertiliser. This is complemented with a top dressing containing a slow release fertiliser with a nine month lifespan. 

“We are working hard with the plants because it’s an unnatural growing method that demands a lot of the plant. It is intensive farming so we have to put a lot back in to give the plants what they need to thrive,” he says. 

He suggests the roses can lose vigour, especially with age, and that the challenge is providing sufficient nutrients to reduce this. 

“The roses are susceptible to powdery mildew, downy mildew, rust and botrytis. We do move some plants around to give them a new lease of life but we are limited on space so we have to do what we can with the land and resources we have available,” he says. 

This has led him to seek out products that can alleviate some of the threats and strengthen the plants. 

“I’ve been trying different methods for over 15 years and recently I have been using biostimulants because there isn’t the variety of insecticides and fungicides available anymore,” he says. 

Working with agronomist Gerry Strydom, from biostimulant specialist Orion FT, he has been able to develop a new tank mix that includes the silicon biostimulants Sirius, Rigel and Trident. 

“It has been over a year now and I have seen a change in rose vigour. The stems are thicker and head sizes are larger, which are always a good sign. It has been very dry this year so botrytis hasn’t been a problem because it hasn’t been humid. However, pests including green fly, black fly and aphids have been markedly worse,” he says.

Silicon that can be made plant available helps to strengthen the cell walls of plants and increase leaf hair density. This makes the plant harder for biting insects to penetrate and makes the plant less palatable.

“We have lost fungicides, so we have had to look at other alternatives. We have a sister farm in Kenya and they wouldn’t use any of our fungicides, and we can’t use theirs because they aren’t approved for use. We are limited to three or four fungicides but they are outdated and not really fit for purpose,” he says. 

In the past, he has tried seaweed products and SB Plant Invigorator to help the roses withstand insects, but neither were effective. 

“Silicon products I used years ago had the potential to scorch plants but I haven’t experienced this with Orion’s silicon range. Instead, I have noticed that leaves are stronger and I am using less insecticide to manage the rose crop,” he says.

He applies Sirius at a rate of 100ml to 200 litres of stock mix, and this is diluted on to the crop at one percent. 

“It is fed through the drip irrigation and I also use Rigel and Trident at 500ml to 500 litres of fungicide mix, which is applied over 0.66 of a hectare once a week,” he says.

The perennial Scabiosa crop is given the same spray and feed as the roses. However, these are used against powdery mildew, spider mite and caterpillar.

“The caterpillar threat has been lower this year but spider mite has been concerning. It is the highest I have seen in over 20 years because the conditions have been perfect for them. We try not to use insecticides, so as to not harm beneficials including Phytoseiulus which are introduced in the spring and summer,” he says

The predatory mites are used to kill the spider mites, but he has had limited success and suggests that strengthening the plant has been of equal importance. 

“Rather than use insecticides that threaten how effective the beneficials are against spider mite, I have chosen to use the biostimulants that help strengthen the plant against biting insects without endangering them,” he adds. 

He feeds Sirius continually through the drip irrigation system. It provides 21 percent bio-available silicon which helps nutrient uptake and usage to enhance plant health. This high concentration of silicon in the plant, stimulates growth and helps the plant to deal with stress, including extreme temperatures and pests. 

“The hydrangea crop has suffered with vine weevil which we use nematodes against. However, the nematodes are hit and miss and this year they have been better. The environmental conditions have to be right, so we had to water them in this year. We also used Sirius this year and that could have had an effect on the hydrangea, the plants certainly seem to be stronger and have more vigour,” he says. 

With 200 different flowers, foliage, herbs and ornamental grasses being grown, the challenge has been to find solutions that cover the majority of the farm in addition to specific treatments for individual species.

“I have seen the silicon products provide all the plants with a boost. Like everything, it is not a solution on its own, but it is complementary to our system, especially as we are trying to reduce our use of chemicals. I will be maintaining it in the mix for the year to come because it has shown promise and is a sustainable way of managing the crop,” he concludes. 

We have developed novel product formulations that stimulate natural plant defence mechanisms, with application across all sectors including agriculture, horticulture, ornamentals, amenity and forestry.

To speak to a member of the team to discuss your requirements, please Contact Us today.