My five pillars of nursery management

By Patrick Gorman, Fernland’s agronomist

As an Agronomist and Head Grower, Patrick Gorman has been fortunate to work with many of Australia’s leading nurseries and has been mentored by some of the nation’s best growers, scientists and business owners.

Patrick attributes his own nursery growing practices and those of top nurseries around Australia to five key areas of nursery management: Irrigation and Moisture Management, Soil and Plant Health, Plant Nutrition, Pest and Disease Management and Weed Management.

Irrigation and Moisture Management

Before the seedling is potted, it is critical to have the relevant water infrastructure set up to supply the nursery. This may come from rainfall, irrigation schemes, dams, bores or even town water. Ideally, irrigation water should be free from bacteria and pathogens, low in salts, and free from algae-causing nitrogen or phosphorus run-off. However, this isn’t always so. Dam in-flow wetland areas can be used to filtrate captured run-off, with irrigation water further improved – in the dam – using aerators and chemical applications.

Water disinfection is a common practice nowadays in most nurseries and is key to reducing pathogens and viruses that may be present. Common treatment options include sodium hypochlorite, chlorine dioxide, ozone or hydrogen peroxide.

Moisture Management in the nursery is the next step to healthy, balanced plant growth. Daily moisture records and laying out plants according to their size and moisture/light requirement, ideally within certain irrigation zones, will all contribute to a more uniform plant and crop. Moisture management in the nursery is the most challenging skill to learn; however, when implemented correctly, it leads to healthier plants free from soil-borne diseases, root rot and or tip burn and die-back.

Soil and Plant Health

Soil media health, whether it be in-ground or in a plastic pot or bag, is critical to the overall health of a plant. Most varieties thrive in porous, well-drained soil, with the ability to retain nutrients and moisture, which provide growth and root development. Ideally, most soil profiles and medias should aim for a pH of 6–7 and a cation exchange capacity (CEC) above 10. The CEC is the soil's ability to hold onto cations (mainly calcium, magnesium, potassium and sodium). Incorporating organic matter and increasing the humus in the soil will also improve soil structure and the CEC value.

In addition to soil inputs, soil biology plays a crucial role in nutrient availability, resilience to pests and diseases, and the ability to withstand and overcome severe environmental conditions. Although naturally occurring in limited quantities, applying products containing bacillus species, Trichoderma and/or mycorrhizal fungi contribute to increased plant growth and quality. Just like humans need good gut flora, so do our soils, and these types of biologicals are the soldiers doing the heavy lifting.

Plant Nutrition

Plants, like humans, need a varied and balanced diet. Major elements like nitrogen, calcium, phosphorus, potassium and magnesium are required in larger amounts, while trace elements like boron, zinc and copper are needed in smaller doses. The addition of lime/dolomite and potassium products incorporated in soils or media will help ensure that ideal levels of major nutrients are available. Controlled-release fertilisers provide an ideal and very stable base, with many NPK variations available to grow great plants.

Fertigation, applied to soil or foliar, is also an excellent way to deliver plant-available nutrients for quicker uptake. This option is great if plants require frequent feeding or additional nutrition is needed owing to accelerated growth or during periods of adverse weather conditions. Ideally, incorporating all aforementioned fertiliser options will (yes, take time) ensure optimal plant health, which means more plants out the door faster, month on month, year on year.

Pest and Disease

Pests and diseases vary and differ with each environment and location, but they are also influenced by soil health, moisture management, and plant nutrition. Plant growth and quality are intrinsically linked to disease resistance; the better nurseries prepare their plants from the start, the better their plants will cope with pests and diseases. However, fungicides, insecticides and biological agents are all required to maintain healthy plants during periods of high pest and disease pressure – to ensure commercial viability and saleability of the crop.

Strategies implemented by Australia’s leading nurseries include spray records with excellent note keeping, some calling them ‘Trigger Points’ from months/years gone by, so they are prepared for each month, each year. This is an excellent practice and ensures a proactive, preventative Pest and Disease Program can be applied as required.

Different crops and varieties require different programs, some soft and IPM friendly, and others more severe, so as to avoid negative economic impact. There are many pesticide options, including a range of beneficial predators, and an experienced agronomist will work with a nursery to find a balanced program that suits their environmental, economic and social goals.

Weed Management

Weeds starve plants of nutrients, reduce uniformity, waste vital irrigation water, slow down dispatch and leave a massive hole in the hip pocket of business owners. However, this need not be the case; with diligent management and proactive programs, it can be overcome. A three-pronged, prioritised approach should provide the framework to limit weed growth, save labour and speed up dispatch:

1. Pre-emergent herbicides: Using granular or liquid herbicides on the tops of pots will stop seeds from germinating and spreading.

2. Spraying the tops of pots/interrows and surrounds: Using knockdown and pre-emergent herbicides to spray around plants will keep pads/paddocks clean and hygienic.

3. Ground spray driveways, pads and boundaries: Preparation prevents poor performance. If we maintain clean growing areas and push the boundary of weeds further from production areas, weed pressure will decrease.

Manual removal of weeds is the other critical and essential aspect of Weed Management. All paddocks or grow areas must be systematically weeded (ideally before pre-emergent applications on tops of pots), week by week.

The above information may be familiar. However, it is the ability of a business or grower to consistently implement all of the above ‘Pillars of Nursery Management’ that will ensure a productive and successful nursery. If you would like to discuss any areas of Nursery Management further, please get in touch with Patrick on 0456 800 972 or Patrick.G@fernland.com.au.