This is my own experience in our small commercial greenhouse. We aren't on a major scale and we do all of our own work. I prefer wood to anything else. With wood I can add a section, replace a board, nail on a new shelf, add on, etc. Everything is fixable immediately at low cost. I can work with wood but when we've had plastic benches and they weren't quite the right size or it cracked then there wasn't much I could do with it. I haven't had any axperience with metal units. I just like the way the wood smells, washes off, holds some moisture around the plants...but mostly it's versatility in changing layout (which you will!). Labor costs are a big part of our expense and the more I can do myself the better.

Sweetpea,

If you are using heat-mats stay away from plastic. The heat slowly weakens the plastic, so you will have to replace more often. Plus why add a fire hazard if something goes wrong with a heat mat? The metal tops will last longer and are just as easy to disinfect as plastic. I just spray mine down with bleach between crops and now and then replace the non-flamable foam insulation I use under my mats. Just watch for rust under the mats and hit them with Hammerite paint as needed.

Good luck,

Hap

I second the vote for wooden structures. Cheaper and more versatile.

Lobster pot panels on a wooden frame work pretty good here.

I've had some VERY extensive experience with plastic and I can tell you for sure that most of the above-mentioned concerns are nothing short of silly. First of all, heat mats will not weaken the plastic over time. Most plastic benches are heat injection molded, which means that heating will actually tend to strengthen the material. If you want to waste every season replacing rotting wooden planks and making vain attempts at decontaminating porous or rusty bench tops, go ahead. I'd rather spend my time and money finding ways to improve overall yield. Secondly, you can get plastic benches with plastic legs that seem to NEVER rot or crack. I know at least three people who have used the same plastic benches and legs for more than 15 years. The key is to buy the really heavy-duty ones, like you the ones you see as displays in the garden center at Wal-Mart. I was able to find the phone number for the manufacturer on one of the benches they have there. Try plastic before you scoff, you'll be thanking me in about three years.

Most plastic benches are heat injection molded, which means that heating will actually tend to strengthen the material.
Not

By routinely heating pvc that has been autoclaved or pelletized and mold injected weakens the molecular makeup of the pvc. ( In my college years I worked in design research and development for an injection molding company while paying my way thru college )

I'm not a professional nurseryman, but I have small greenhouse and enjoy the rather expensive but great looking + performing stainless steel work bench and galv. metal frame benches.

Easy to keep clean, no worries about the heating pads or coils, looks great when doing presentations in the greenhouse , good long term investment overall.

The benches would probably be pretty durn expensive to outfit a commercial greenhouse facility with, but they sure are great looking, long lasting ,hard working product.

Old Asian proverb says :
' Man of many knives , but none of them razor sharp. '

believe me, I have lots of thoughts, but they may be quite dull.

Having watched a 48' by 96' hoop-house go up in a cloud of very toxic smoke... just because of a one year old heat-mat wigging out, frying the thermostat and then melting-down and setting plastic benches on fire... I have to say I would not risk using heat-mats on top of something flammable.

That does not mean I would not use plastic benches to hold standard stock, just not in combination with heat and electricity.

I suppose anything would burn in circumstances like this. Also, the benches I'm talking about are HDPE, not PVC. I don't know if this makes a difference.