Improving water management in nursery applications

Wetting agents can save water and labor costs by correcting several challenging nursery situations

March 16, 2022
3 mins

No doubt you have seen it happen in your nursery, along the edges of plant beds or the sides of tunnels. You’ve measured moisture levels in the center of the beds and they’re looking fine. But no matter how well your irrigation program is set up, the sides of the plant beds seem to always dry out faster. You are facing the challenge of re-wetting growing media using water and labor you can’t afford to waste. Especially when switching from peat-based to peat-reduced or peat-free growing media, you may need to reevaluate your water management program.

The challenge with dried-out substrates 

Substrate can become water-repellent, or hydrophobic, if it has been left to dry out over several irrigation cycles. Once a growing medium becomes water-repellent, it can be very difficult to get moisture levels in the pots and containers back up to optimum levels. Water will no longer permeate the substrate efficiently, leading to runoff and loss of (water-soluble) feed. 

Water-repellency can become most apparent in peat-reduced and peat-free components of growing media. These new growing medias often have a much lower water-holding capacity than typical soil. You may need to water more frequently or use more each time.

Specific areas on the nursery field run the highest risk of developing hydrophobicity—the edges of plant beds, plants in the air flow from ventilation windows in greenhouses, plants getting direct sunlight, or in exposed to dry winds. 

Ideally, water levels in pots and containers should be kept constant, and that’s where it gets tricky—watering is something most growers tend to do “by feel.” In many cases, the center of a plant bed is used to determine whether the block needs to be watered. If the plants in the center are at targeted levels, then that block of plants may not get a full round of irrigation. 

Unfortunately, by the time the plants in the center of the beds start to dry out, the plants along the edges will already have been dry for a while. Watering more frequently by hand can become necessary to keep the edges sufficiently moist and in good condition. 

The importance of water 

Water is a plant’s most essential mineral and plays a key role in:

  • evaporation and transpiration, as it helps to lower leaf temperature 
  • building strong stems and leaves 
  • the transport and uptake of nutrients 

Without water, there can be no growth. So, creating an environment with efficient nutrient transport is crucial. 

The role of wetting agents in dried-out pots and containers 

Wetting agents can play an important role in several challenging nursery situations. 

In spring it can help to kick-start early spring hardy nursery stock and herbaceous growth by aiding the initial wetting of plugs. Generally grown as dry as possible through the winter, at first watering it can take several attempts to get plugs sufficiently wet to apply liquid feed. This can be overcome by adding a wetting agent that quickly infiltrates the plugs. 

If about 10–15% of a plant bed consists of edges, that’s 10–15% of pots that are prone to dry out at a faster rate. That same 10–15% will likely have issues with growth and difficulty taking up nutrients. Applying a wetting agent ensures that water can spread evenly throughout the pots and containers, infiltrating water-repellent media, and ensuring the whole pot becomes wet. Pots will stay sufficiently wet for longer periods, especially along the edges, requiring less frequent irrigation and reducing labor costs.

Another capability of wetting agents is improving shelf life by maintaining pot and container quality, both along the supply chain and in the retail environment. When applied prior to dispatch, the wetting agent will ensure the pots and containers become wet quickly and will make the most of any rainfall or limited irrigation.  

If you are looking to improve your water management and reduce labor, incorporating a wetting agent such as H2Pro into your substrate or adding it to your irrigation water could be the answer you’re looking for.