Black Trays & Sunlight

We often get asked how our trays react in various different environments. One concern for growers is how our black plastic propagation trays cope with being in direct and intense sunlight for extended periods. We address this below and explain how our trays are still the perfect choice, even in hot growing areas.

Potential UV Damage

Black plastic is actually the strongest against sunshine. 

Our black plastic contains the additive Carbon Black which is one of the best, if not the best, UV inhibitor. This means that black can stand being in the sun longer than any other color.


Proptek propagation trays and containers are designed to be long-life and are very study, so it will be a very long time indeed before the trays become so weak that the risk of cracking or breaking becomes an issue, even if they are discolored.

Bleaching of trays to gray or white is very, very rarely seen, especially on a black tray.  In fact, we’ve never seen a bleached black tray, but certainly have with other colors such as red, which is notoriously bad under UV conditions.

Overheating Trays

Overheating trays has never been negative in our experience. This slight increase in diurnal temperature range, and along with irrigation frequency and volume, just needs dialing into the growing program to make it work well.

Our trays are black and therefore do warm up more in direct sunlight compared to a white tray, especially when compared to a Styrofoam tray.  For our black plastic trays, the opposite of course is true: they cool off quicker at night, meaning there’s a larger diurnal temperature range.

We have a lot of customers in hot climates who use our black plastic propagation trays who achieve excellent results that are far superior in both plant quality and cost effectiveness when compared to white Styrofoam.


Proptek trays do get warmer in the sun and can experience slight discoloration on very rare occasions, but this does not normally negatively affect the lifespan of the tray, nor the quality of the seedlings produced. The above is a guide – the climate at every nursery is different. If you are unsure, please get in contact for advice and to arrange samples for trials.

If you would like any more information or any clarification on any of the above, or you would like to discuss any aspect of our trays, please don’t hesitate to get in touch.