Growing orchids indoors

Your query has many answers, Mark.

LEDs will be a better bet for you, based upon electrical efficiency alone. A bigger investment up-front perhaps, but a definite savings, long term. It is not absolutely necessary to purchase "plant lights", either; white LED outdoor floodlights work quite well. Just get the maximum wattage you can. The most I've seen in the US are 115V, 20W, and they are bright!

I would avoid "converted terraria", as they are somewhat cumbersome to work with when watering and handling your plants, and I suspect the cost would be exorbitant considering the number and size needed to adequately contain your plants.

What is your indoor temperature and humidity in winter? If you can maintain minimums of 15-16C and about 50% RH, you should have no problems without enclosing the plants, so any kind of table, stand, or shelf would be adequate.

When I went from 35+ years of greenhouse growing to indoors, I culled my collection to a number I could accommodate (1000 plants were NOT going to fit, let alone do well in the house), then outfitted "bakers racks" (utility shelving), removing some of the shelves, affixing lighting to the ones above those holding plants, and enclosing the entire thing with a humidity tent.

I think you'll accomplish what you want, but you'll need to be creative.

 

Mark, I advocate for building your own.

My main space is an 8' x 2' x 6' tall enclosure, with two levels, made of common building lumber.

I have two trays lined with vinyl swimming pool liner, with walls composed of styrofoam insulation sheets.

Currently, I'm using 8' fluorescent lamps (High Output) driven by electronic ballasts *outside* the enclosure. There are bulkhead fittings in the trays to drain excess water.

All of this is in an unfinished basement.

Because I like cool-growing plants, I installed an air conditioner in a window, and have insulated ductwork leading to the two levels of the cabinet, with the ability to shut down either independently. This generally lets me get nights down to the mid-50s during the warm summer nights here. I also have a way to import outside air directly to the enclosures when artificial cooling isn't needed.

For humidity, I have some misting nozzles run by a pump that allegedly produces 150 psi. With this, fans are necessary - I have been buying cheap ones from Walmart, and placing them where they won't get too much water. When the bearings sieze, after several years, I bin them and get new ones, they're less than $10 US each.

A woman in my local club actually disassembled her green house, and reassembled it in her basement, and now grows her plants in there, using LED lamps.

Hope this helps

 

Looking at the Dublin climate data, it would be perfect for growing high altitude cold growing orchids! Since ambient RH is very high (80%) in the region, you probably don't need to have enclosures. Depending on how well your house is sealed, the RH can be lower in the winter, but you probably have enough humidity for Paph and Phrag. So just shelving units might be all you need.

How much bench space do you need to cover your plants? Then you can calculate the cost of electricity required for lighting, and compare it against the cost of heating in greenhouse. Probably, keeping them in the greenhouse during the summer, and moving them under light in the winter would be most economical. Especially, in Dublin, you don't seem to get lots of light in the winter, so it will be helpful for plants.

The most expensive part of indoor growing (both initially and long term) is the light. If you have windows with good light, you can reduce the cost, but you'll probably need some artificial light. With the top-of-line LEDs (DIY-type high efficient LED), about 100W per m^2 would give plenty of light for these species. But with cheap LED light, you'll likely to need 1.5-2x more electricity.

This is something I would buy at this moment:

Bridgelux EB Gen 2 LED linear module (4000K, 112cm) (18 euro)
BXEB-L1120Z-40E4000-C-B3 — Octopart

Meanwell GSC-40E-700 driver (15 euro)
gsc-40E-700 — Octopart

This combination gives 27W of high efficiency light, and it will cover 120x30cm area easily for about 35 euro. All you have to do is strip wires from 2.1x5.5x11mm connector jack (which you have to find), and push it into the push connector of LED strip. The driver is already wired with E, and you don't need anything else other than attaching it to some place by string or duct tape. If you can do wiring, you can save money by using one driver to multiple LED modules.

If you go with commercial light, you'll need to pay quite a bit more (and a bit less efficiency). If the electricity is expensive, it is a false economy to get cheap grow light fixtures. It looks like in Ireland, electricity is about 0.24 euro/kWh (which is quite expensive), so 100W for 1 m^2 cost 105 euro per year with 12h light per day.

 

You can grow plants in red/blue or white LEDs. But at this moment, I don't see any advantage of red/blue. White LEDs have increased efficiency dramatically and decreased the price. So for a given cost of diodes, top-end white LEDs have been more economical (higher efficiency/cost). LED outdoor flood lights are still around 110lm/W, so even if it is free, it is cheaper to buy a higher quality light which is around 180lm/W (since your electricity is expensive).

 

Mark, my recommendation is Bridgelux EB strip (links in msg #4), which is pretty much hang and plug-in. I'm not so familiar with European market, but I know these are available. For commercial grow light, I know Fluence (link) and Phillips Horticultural LEDs (link) are high quality. But with your initial budget, only a small space is covered. So if it is ok to pay more for electricity later, you can pick whatever highest efficiency you can afford. I think you can get fairly cheap LED shop light. They are around 100-110 lumen/W in the US. You can check the lumen value and ACTUAL wattage to calculate the approx. efficiency (efficacy) to compare the models. Higher lumen/watt means that it produces more light for a given electricity consumption.

 

I am finding this all very interesting. I live in an apartment so I have been using the second bedroom as a grow room. I have one window facing SE…into trees, so I bought a 4 ft table (adjustable by height) at Home Depot; purchased a couple of fairly sturdy chrome garment hangers. I have 4 ft. LED lights hanging from the garment hangers over the table. My dendrobiums, my one cattleya and one vanda hang out in the middle on humidity trays. I have an assortment of shelves around the perimeters of the table for the Phals. and Paths. I have a bakers rack with T5 grow lights for the Neos. and a growing tent for my mounted, warm growing/hi-humidity orchids. There are three fans going 24/7: ceiling, left pulling air from outside of the room and the right fan is an oscillating floor fan. I keep a humidifier going 24/7 set on 60% humidity.

 

Yes.