Page 38 - Simply Vegetables Spring 2021

Damping Off Control
Damping off is a common and devastating disease of young seedlings grown in seed trays in greenhouses and poly-tunnels.
It can occur outdoors but is less common and is usually a sign
of sowing too thickly. Years ago Cheshunt Compound was widely used to control the disease by watering a solution onto the compost before sowing and again if required after germination if
the disease occurred. It worked very well was not too expensive, but was withdrawn a few years ago I believe because it was not financially viable for the chemical companies to register it for use. Commercially there are other chemicals available to the growers but for amateur gardeners nothing has replaced it.
I recently read the following advice which I thought I would pass onto members, although it has not been through the approval process as
it only contains water and white vinegar there is nothing to harm the user, environment or consumer of the crop. As they are both used in food production there are pretty harmless!
Use 1 part white vinegar to 3 parts water and water this onto the growing medium before sowing
to control damping off, if it still occurs use on the infected area. If your seedlings regularly suffer from damping off you need to consider why? It is either dirty boxes or containers, infected compost (not sterilised if a soil based compost) or dirty water; eliminate the problem and your seedlings will be healthier.
Another interesting tip I read (well I thought so!) is to soak seeds before sowing to speed up the germination. You are probably thinking I have been soaking my peas and beans for years, where has this guy been? Well I have also often soaked the peas and beans and it does help germination, but this tip was to
soak carrots and lettuce seed which owing to the size I have not considered doing.
The advice was to soak the seed overnight, drain carefully through a fine sieve (the type used for sieving flour, but don’t tell the cook!), mix
the seed with fine dry wood ash
and leave to dry a bit so they do not clump together when sowing. Once ready sow as normal as per the seed packet instructions.
38 Simply Vegetables
Seaweed Products
The following information came from a training YouTube for professional growers by one of the large chemical companies who sell a range of fertilisers to the growers and I thought some of it may be of interest to members.
There are a number of seaweed products available to both professional and amateur growers, some are sold as pure seaweed solutions others have added ingredients such as iron or non-organic fertilisers (called co-formulants). The products can vary quite a bit depending on the species of seaweed used, how the solution is extracted from the seaweed and the concentration of seaweed in the product. When using the product the application rate and method can also make a difference.
Seaweed products are often sold as biostimulants rather than fertilisers or
feeds. There are a number of species
used to make plant biostimulants and
these include macro algae which can be red, green or brown depending on the species. Different companies use different species often depending on where they
are harvested from; the, main areas are
the coasts of Ireland, Norway and South Africa there are no doubt other locations. These are mainly tidal areas as this results
in a sustainable product as the seaweed regrows fairly quickly after harvesting and can be harvested again in a reasonable time. Ascophyllum nodosum is one of the algae used in at least two products.
So what does seaweed extract contain? The following are some of the materials:
• Polysaccharides
• Minerals
• Vitamins
• Oils
• Fats
• Acids
• Antioxidants
• Pigments
• Plant growth regulators (hormones) There may be others depending on which
species are used.
As mentioned above the product is
affected by how the liquid is extracted from the seaweed, at present there are three main methods:
Water based where the seaweed is chopped up pressed and hydrated.
Acid extraction where an acid is used to extract the liquid.
Alkaline extraction where potassium hydroxide is used.
Some companies play on the water based method being more organic and a better option.
Benefits of Seaweed Biostimulants.
Better plant growth and quality.
Nutrient uptake from the solution.
Better abiotic stress tolerance.
Better biotic stress defence.
Abiotic stress is where a plant suffers
from wind scorch, frost damage, or other weather damage including drought. Nutrient deficiencies, salt damage, transplant shock, root damage, or other problems not caused by pests or diseases, biotic stress is plant damage caused by a living thing like pests and diseases.
Better chlorophyll is also claimed and helps to maintain photosynthesis.
Higher yields and quality.
Better shelf life (more for commercial growers, but applies to gardeners who wish to store the crop for a short while).
Better nutritional quality in the plants.
Better vegetative growth.
Gives better seed germination and growth. How many of the above can be proven I am not sure, possibly all of them.
Methods of Application:
Watering the plants whether in containers or open ground.
Foliar feeding.
Adding to the growing medium (usually as flakes of seaweed).
Seed treatments like soaking.
I know a number of members use
seaweed products often along with other feeds and presumable get good results. They are not new and I can remember using Maxicrop when I was a youngster more years ago than I care to think back. A pure seaweed product is organic so can be used by organic growers. If you have not used them it may be worth giving them a trial; certainly the seed soaking looks interesting and worth a try.