A Booth

Hi everyone. I have a small nursery which is Certified Naturally Grown and I have a question about organic fertilizers. I have tested my nursery soil and the soil of certain plants during different grown phases and have found that while P and K generally stay sufficient for a long time with the organic fertilizer blend added to the potting soil the N gets diminished pretty quickly. I then supplement with fish emulsion which is stinky in a greenhouse, expensive and doesn’t seem to add as much nitrogen as my plants really need to grow efficiently. A local company that specializes in wholesale organic products for growers had something called Grower’s Secret Professional and I believe Down to Earth organics has a similar one. It is OMRI certified, is water soluble and has very high nitrogen for organic at 14-0-0. It is made from soy which has me a little suspicious. I’m wondering if this is too good to be true. Can’t it still be OMRI certified even if it is made from conventional soy meaning that even if there is very little residue remaining it still poses the ethical question that large amounts of pesticides and possibly some inorganic fertilizers were used to grow that soy? Could even be round-up ready soybeans? I’m sure it works...just thinking that if I morally prefer to reduce my impact on the planet, this may not be the right choice, especially since it is probably virgin materials rather than a byproduct like many other organic fertilizers. Interested in hearing from anyone who can confirm what I already suspect (or disprove it ideally). Thanks.

Brian Karlsen wrote:One thing to concider with a propane heater is while it adds some co2 it will also be adding humidity another option for co2 adition is to take up home brewing and put your fermenters in the greenhouse.

I actually used to be a home brewer (and worked in a brewery for a few years) but alcohol gives me serious acid reflux and I have to take Prilosec daily to keep it from further damaging my esophagus so I avoid alcohol now. Fortunately a local store now carries some decent non-alcoholic craft ipa and stout so I don’t have to give up beer which I love! Maybe some day when I have more time I’ll try to make some N/A beer.

I have found that my greenhouse stays in the 700-900ppm range of co2 on its own. I’m thinking maybe it has extra co2 because of composting organic material under the floor since I rototilled and leveled a grassy area before putting down nursery ground cloth and constructing the greenhouse. I have just been running the propane for a few minutes several times a day because it bumps it up way above the desired 1000-1300ppm levels very quickly and therefore doesn’t seem to be a good option for heating my greenhouse. I’m now looking into a 240v electric heater since the greenhouse is near the previous property owners machine shop which is set up for lots of 240v machines. Right now I’m using two 120v heaters on separate breakers but it gets cooler than I would like on really cold nights.

Thanks everyone, I ended up getting a compressor style and it’s been working wonders in the greenhouse. Brought it down from about 80% RH and holding it around 60% RH. Hopefully no more botrytis like I had last winter. The added heat has also been welcome, it’s not much but I think it raises the temp at least a couple degrees.

Thanks for the suggestion. I’ll likely get something like that or other commercial grade greenhouse controls in a few years when I build a permanent steel frame hoop house. I own a small landscaping business but am transitioning to solely design and growing the nursery on our land. Right now it’s in the very early stages so I’m just trying to get some semblance of climate control even if it isn’t perfect to get me by and to hopefully grow some plants to fund greenhouse upgrades.

I did more research and found a small propane heater with a low oxygen shut off and also got a carbon monoxide detector just in case. I may also get a basic co2 monitor and just to try to balance it manually. The two electric heaters I had didn’t quite seem to be able to keep temperatures where I wanted them so the added propane heat is a bonus in that regard.

As for the dehumidifier I’m still weighing the options and having a hard time committing without having much experience with either.

M. Phelps wrote:dont think you are going to like the price tag but search

Grozone SCO2 The Simple One

and

Titan Controls CO2 Regulator

i would get a burner though... they can be nat gas or propane

R Scott wrote:I can't remember the name of the compound off the top of my head, but the same thing that is in damp rid is available in bulk from many farm supplies (and sidewalk deicer.) hang it in mesh bags above five gallon buckets.  $200 buys a lot

It is Calcium chloride. I’ve read that it is a skin, eye and lung irritant and long term exposure in a closed environment like a greenhouse with lots of fans blowing particles around could lead to permanent lung damage.

I’m gonna go with a plug in dehumidifier but hoping to get some input from someone who has used them successfully in a small greenhouse before.

Hi there, my wife and I opened a small organic perennial nursery last year near Portland, OR (Zn 8b). We have a 15’x 40’ hoophouse that is about 8’ tall. Im estimating about 3500 cubic ft of air space inside. Last year I had a jerry rigged hoophouse inside of a hoophouse set up that made it dual wall insulated which enabled me to keep it about 60 degrees with a couple space heaters. The problem was that it got very humid inside even with regular ventilation because the winter air here is so humid that ventilation alone doesn’t seem to dry it out enough. I used multiple box fans for air flow and to try to keep plant surfaces dry but it wasn’t good enough. While I still managed to grow many healthy plants, I definitely suffered some losses due to fungal diseases. This year I am making a few upgrades before winter including an inflation blower for a better dual wall system and I am looking into a dehumidifier to help keep the humidity down.

From my research it seems that desiccant dehumidifiers are preferable to compressor dehumidifiers in greenhouse applications because compressor styles can develop fungus inside them and blow spores into the greenhouse air. They also produce a little very welcome heat while I believe (but am not sure) compressor styles cool slightly. They also work better in a wider variety of temperatures and humidity levels. The main reason I am wondering if it is the best choice for me is that I am on a budget and cannot afford a more powerful commercial grade desiccant dehumidifier this year. At the $200ish price point I can get a 10-20 pint a day desiccant style dehumidifier which I really have no idea if that will be enough. Or for roughly the same cost I can get a 50-70 pint compressor style. Considering I will be heating the air to 60-70 degrees I would guess that the compressor style could operate at close to maximum capacity meaning much more bang for the buck in terms of water removal am I correct? However, if it does spread mold spores or cools the greenhouse too much the increased water removal may not be worth the other risks it poses. Does anyone have experience using either style of dehumidifier in their greenhouses and how do they seem to work?

One one more related question. I have heard that if I don’t get some outside air exchange there may not be enough co2 in the greenhouse. I will still open the greenhouse for cooling during our occasional sunny winter days. However, on cloudy days if I want to keep the greenhouse closed to hold in heat and air that has been dehumidified can I use a co2 tank to add supplemental co2 (I have a 20lb tank that is not being used) or is the co2 deficiency in a closed greenhouse too great to avoid regular outside air exchange?

Thanks in advance for your help getting my greenhouse microclimate dialed in.

Thanks everyone, I think I’m gonna go for it and do some trials where I do some of the same batch of plants with and some without and maybe try a commercial organic fertilizer as well to compare.

I thought my situation was unique in that the traditional reasoning behind composting it first did not apply but I just wanted to make sure there wasn’t another human health or plant health reason not to use it straight.

Michelle Heath wrote:Chicken poop will burn plants, edible or ornamental, if used fresh.

I’m fully aware that using straight chicken manure is very high in nitrogen and will burn plants. The high nitrogen however, is precisely the reason I want to use it. As I mentioned I plan on diluting the tea down to 1/16th strength which seems like it would be enough? I could dilute further if necessary, in theory it seems to make sense that that would work to reduce the nitrogen enough? I would of course test it out on small batches of plants before watering the whole nursery with manure tea.

Hi everyone. My wife and I purchased some acreage a couple years ago and have started a micro nursery which is Certified Naturally Grown. As far as I know we are the only nursery in the Portland Metro Area that grows ornamental landscape plants (Perennials, Grasses, groundcovers and shrubs) without synthetic fertilizers and pesticides which are really very common place in the nursery trade. We saw a niche market to fill but also really wanted to provide a more sustainable alternative to our community. We recently got some laying hens to provide eggs for our own consumption and to make use of our food scraps.

I am hoping to collect their poop when we clean their coop and use it as fertilizer for the nursery by making a tea in 5 gallon buckets with an aerator. Most advice I have read on the subject suggests composting it first to reduce the nitrogen and the risk of food borne pathogens. However since most of these plants are not intended for consumption with the exception of some herbs which I could avoid using the tea on I’m thinking the pathogens would be a non issue as long as I washed my hands after working with it. The other purpose of reducing the nitrogen I think also does not apply because I want a high nitrogen fertilizer to help the plants reach maturity as quickly as possible. I would still significantly dilute the mixture with a hose attached siphon mixer that mixes at a ratio of one part chicken poop tea to 16 parts water so I doubt it would burn any plants.

Does anyone see any reason why I would still need to compost it? I would likely also add some on farm produced yard debris compost to the tea also for additional nutrients and bioflora. Thanks!

Mike Jay Haasl wrote:Hi A, I've seen something similar myself.  I believe the University of Minnesota has what you're looking for.  Do a search for Deep Winter Greenhouse and their design should come up.  It's a 4' deep gravel basement under a well built greenhouse.  

Thanks, I looked into it a little more, they didn’t give a lot of specifics but gave me the confidence that it had been done successfully before to try it. I had enough materials on hand leftover from my landscaping company’s jobs and home projects to build the underground river rock air chamber without any investment. It’s a smaller system but I figure if the 2 hours I put into it raise the temps of the 240 sqft dual wall poly hoop house I will put over it a few degrees in the winter it was worth it to get a head start on the spring for the perennials I plan to grow in it. I am in zone 8 with temperatures at night above freezing more often than they are below so a few degrees may get it to the point where some winter growth will occur.

I have a 24” auger for my mini skidsteer that I use for my landscaping company so I used that to drill a few holes about 5’ deep and I finished it off by hand after the bulk of the digging was done with the machine. I lined the hole with landscape fabric to filter out soil. I put about 8” of river rock in the bottom and then installed two 6” air duct pipes I pulled from my crawl space since we have a ductless heat pump in the house now. I used a bunch of scrap ABS pipes for the exhaust that I had left over from drainage work my landscape company did.

Now comes the part I am not sure of. I plan on purchasing two 6” inline fans for the 6” air duct inlets. What I am not sure of is how to use both fans at the same time for both heating and cooling. To keep this project cost to a minimum I was hoping to use a basic $30 dual stage thermostat from amazon, the type with a temperature probe and an outlet for heating and outlet for cooling. What I then realized is that those thermostats are designed for a heater on the heating side and an AC or fan on the cooling side but not using the same fans for both because it has two separate plugs for heating and cooling. I thought about doing some sort of spliced wire to plug into both with the same fans but after taking with my brother who knows a lot about electricity it sounds like that is potentially hazardous. Does anyone have any ideas of how to utilize the same fans for both heating and cooling? I am open to another type of thermostat (even if it costs more).

My other idea is that I may just have to have it plugged into heating only in the winter and then have another fan to vent greenhouse in the winter if it gets too hot. Then in the spring when I may not need the system working a full capacity I can plug one fan into cooling and one fan into heating. Then in summer I would switch to cooling only.

Any thoughts or suggestions on how to set up the thermostats would be greatly appreciated. Thanks.