Greenhouse growing

Hello all. I recently started a job as a grower in a rather large-scale production greenhouse, and while I have studied botany, this will be my first time learning about vegetable growing in a greenhouse setting. Anyone else here work in greenhouse growing? I am most interested in learning about low-tech, GW ways to use a greenhouse while I learn about high-volume production on the job.That way I feel like I will have a broader perspective, and can use that knowledge in the future to solve problems that technology can't.

Also, tips about greenhouse growing in general, especially peppers and tomatoes (yay nightshades!) will help me learn faster; I appreciate any help!!


ClareBroommaker's picture

I worked in some smallish greenhouses a long time ago. The only vegetables I remember were tomatoes, but there must have been others. More of the business was flowering annuals, tender perennials, ferns, African violets, and tropicals. There was no CO2 enrichment, but sometimes there was a single space heater per house on cloudy, cold spring days. Most of the time it was just hot and humid, as I'm sure you know.

There was some overhead drip irrigation using clipping, moveable nozzles, but at that time a lot of the watering was done by hose with a diffusing nozzle and even by big watering can. Those were some superb cans, so well balanced that they were not a struggle to fill, carry, tip and water with good control. Might have been Hawes brand. Most of the tables were wood lathing set across a slightly sturdier frame which was then set upon concrete blocks for table legs. The whole set up could be moved easily, but it was also sturdy enough to lean on with one hand while reaching for a pot at the back. Most floors were pea gravel chert, but some were roughly poured concrete, underwhich there was probably no foundation. There were trenches dug aroung the outside of some houses to contain a little rain so that the floors would not flood.

There was an old potting machine, noisy, smelling of diesel, and I remember thinking it was dangerous, though now I don't remember why it would have been dangerous. Maybe the deisel fumes. Everything was potted into peat. The only thing I remember ever getting mixed in was Pearlite or Harborlite. but maybe sometimes we used that expanded mica stuff, vermiculite. There was a giant pile of peat dumped out of spoiled (infected) pots over the years. I would have been happy to solarize it and use it, but I don't think they ever did anything with it.

Ferns starts about as big as a pin head were imported from Guatemala I think it was and grown on to imressie size in a separate green house that was smaller so even more miserably hot. Water was always running in there. I think I remember that water spouts were all outiside of the houses, so that a lenght of hose had to run under a wall or through a doorway to hooke up irrigation of watering hoses.

A couple people were certified for pesticide application, but I was not and was not interedted in the task. Those people generally did the fertilizing, too, I think they used a a fair amount of a soluble formula, but now I'm remembering mixing lots of Osmocote into the potting mix--so ammend wwhat I said above about loading the potting machine.

So al, in all, that operation they type that would become unsustainble in very short time--as soon as peat delivery ended.

I guess you know you'd need to figure out a way to grow in local materials, and preferable have multiple materials you could use. Composted leaves, woodchips, sawdust Coffee grounds mixed with real soil? MIght take some looking into and vary according to where you live. I'd definitely look into humanure and urine fertilizing. If you would be growing to sell, then is there any possibility you could tell customers to return pots and punnets in good condition for a credit or for even a direct buy-back? Even our research botanical garden here accepts plastic pots for re-use, so the hodge podge they get is useable. I think they sterilize them in an industrial dishwasher.

Another thing home growers sometimes do is to compost manure right in the greenhouse. It provides general heat as well as direct heat for germinating seeds. It would give off CO2 as well.

There are some good sized greenhouses that are doing aquaculture combined with fish keeping but that is beyond my interest in technicality. Much simlpler would be separate fish ponds whose water is used for occasional nitrogen fertilization. Again, though, I have zippo experience.

A GW issue I see is what materials you would use for your glazing. Real glass? Roll plastic? Something else? My mother who would be 90 this year once told me of a reinforced clear material that people used to seal in porches in the years before plastic. It was lighter weight than glass, and a little flexible and brittle like plastic. She could not remember what it was called, but in the back of my mind, I think even I saw it in my childhood. Someone still living or some old gardening book must have info on a material like that. Perhaps it is still out there.

I feel sure bamboo poles, cedar poles, lodgepine poles, willow branches, etc, must have usefulness in greenhouse construction. I understand if you prefer to go the manufactured route for materials, but if you have the time and access, it would help the next person who would be learning from you and perhaps setting up their own green house at a time when manufatured matierials are ungodly expensive. Even a wateing system can be made from bamboos with the nodes carved out to allow water flow. And don't forget to look into capturing water from your roofs.

Getting long here, but one last suggestion. You can look into the Chinese method of mudbanked greenhouses which have only the southside exposed to sun and which use insulating blankets to hold in heat at night. You can see a video on that at the Clemson University Agriculture website in the collection of videos about peaches.

Wow thanks for all that info! I doubt I might be able to incorporate much of those ideas into the place I'm working now, but they are great for my personal future use. I will keep and eye out for anything I can do to make some GW changes.

David Trammel's picture

Wow, now there are some specific suggestions for you, lol.

What i would suggest is that you try and study how to make a green house a "Whole System".

That is, too many businesses, and I include commercial green houses in that, get away now with "externalizing" their downside costs, as JM Greer has mentioned many times. They keep the profit and then off load the waste and refuge onto the public commons.

Clare's description of the mound of "spoiled" peat is a clear example. There seemed to be no emphasis on reusing or even dealing with the waste products of the operation, just buy more each year. If you can come to the owners with some clear plans on how to make what every one sees as wastes, resources instead, then that I think would be a good use of your time.

And you would carry that forward to your next green house too.

Al that depends though on the owners. If they are just into making a profit then you are better off using your time to learn the life cycles of the various plants, from seed to harvest. I have learned an incredible amount from just letting some plants in my garden live all year and into the next, without worrying about getting fruit off of them.

Please keep us here informed of what is happening at your new job, especially with pictures if you can.

As far as I can tell, I will be in charge of peppers and tomato growing. However, the seedlings have just started and there's not much for me to do in that area yet, so I am learning about the other parts of the operation. I haven't grown vegetables before, so it's all a learning experience! I will have to be using chemicals, as they once did have some organically grown plants but demand was not enough to support continued growing. Perhaps I can revamp that program later and learn from that style growing also.

Thanks for the info!

ClareBroommaker's picture

I understand about just learning what you can right now from the operation as it exists. My suggestions were intended for how you might run your own greenhouse.

Especially if you haven't grown plants at all before, I do think you will learn a lot at your new job! Unfortunately, I found GH work to be just another kind of factory work, for the most part. Very dull, very repetitive, very hot and sweaty. Boring. The owner always advertised his jobs as "heavy labor" even though it was not. He said that only the people who showed up willing and expecting to do heavy labor could really hack it....So some inner reserve to put up with the heat and boredom, a mental life apart from the "factory work", will help you get by.

This is an industry in which many new immigrants work. And that actually adds some possibility for you. If you can speak their language, or they yours, some of them will be able to tell you how they would have accomplished the same growing outcomes under less wealthy conditions. That knowledge could help you in your own future greenhouse.

I worked with immigrants from India. They spoke English well but had been more or less better off city people in India and did not know about growing plants. Later I met a woman from Afghanistan whose English was not too good, but she was able to show me how they grew pepper starts very close together right in the ground, dug them up when about 10 inches tall, and transported them by making a wet mudball around their roots. They could take the plants to market in the city that way. Thus no plastic, wood, or pottery containers were needed. Very simple.

Wow very cool. I have a botany degree and have plant knowledge, but this will be the first time I've seriously grown a massive amount of plants from seed.

That's great that you learned techniques from immigrants! There are none where I am, but lots of many-generation Appalachian people, so I'm sure I can find some old-time mountain wisdom if I look,