FAQ: what type of tray is right for you?

Paul Greenley is the sales director at Proptek and often gets asked what the benefits are of using an injected molded tray over more conventional trays such as Styrofoam, thermoformed or blow-molded plastic.

We asked him a few questions to get to the bottom of why more and more nurseries are choosing this tough plastic option.

How long have injection molded trays been around?

Injection molded, individual cell propagation trays, pots and containers have been around in some form for decades now. Unfortunately, they often cause more damage than good, with tangled and circling roots a common sight. To get a decent container that really improves both your plants and your nursery operation, you need both horticultural and plastics knowledge and Proptek have been manufacturing very effective containers for 30 years.

We see a lot in the news and media about waste plastic being an issue for the environment – surely still using plastic trays is a bad idea if we are trying to be green?

Plastic is a real problem in the world – but we are tackling this issue by making our trays out of recycled material. When the tray reaches the end of its life after potentially a decade or even more, they get ground up and reformed into more trays. Due to the super long life of the tray, far fewer trays are thrown away into landfills than if a one or two use thermoformed pot were to be used.

How are injection molded trays made?

Not easily - molds are large blocks of steel with a cavity in them. Hot, liquid plastic is injected into this cavity and when cooled the mold is opened, and out pops a tray. That’s the simple answer – the time and money that needs to be put into a mold that can often weigh 10 tons – and that’s without the machine doing the injecting – is incredible. But, we’ve been doing this a very long time and we have the knack of it now and we think a little extra hard work is 100 percent worth it for a far superior product.

Is this not expensive then for growers? Injection molded trays seem to be many times more expensive than thermoformed trays.

Yes, injection molded trays do have a higher price-point than a thermoformed or blow-molded container. However, when you factor in that they can often last 10-20 times as long (if not longer), this money is soon recuperated and then you have years and years of very little outgoings on trays. Quite literally tens of thousands of dollars can be saved every year.

What about working with inserts, such as the Ellepot?

An injection molded tray is a must when working with any inserts. It’s important to hold the insert at both the top and the bottom, ensuring it is secure and consistent for automation. Proptek trays do this as well as providing excellent air pruning and root training features to ensure great quality plants.

So injection molded trays are better for plants?

It is very plant dependent – but the vast majority of the time, very much so. Huge improvements can be made in both quality terms and turn around speed. Better plants mean happier customers for growers and quicker turn around speeds mean more plants sold in a year and this all adds up to significant improvements in profitability.

Root circling chokes the plant and should be avoided.

How does simply changing the tray actually help the plants?

Being tough and because of the nature of the manufacturing process, special features can be built into the containers and pots that are impossible to do on a vacuum, thermoformed or blow-molded container. These include air pruning holes and root training ribs. These prevent roots circling and choking the plant and allows for excellent drainage in the cell and improved aeration of the media.

What other improvements does having a tough container allow?

The area we are most excited about is the compatibility with machinery and automation. Serious labor savings must be made in all types of nursery. Automation is the key – but you just can’t achieve it to its full potential with anything other than a tough container. Thermoformed containers have issues with structural integrity and plant pulling and are just not rigid enough for automation.

Paul can be contacted for your questions and comments on (800) 487 1381 or by emailing paul@proptek.com.