Ideas for student run school Greenhouse?

[digitS']

Hencackle you are right about calenulas. However, unless the "unheated" issue is really significant there for JC (who recently harvested the last of her peppers!), I think there'd be more of a problem with heat and the stretching of the plants. Potted, blooming calendulas are commonly treated with a growth retardant.

This would be especially true if you are trying to get a crop thru until June in a northeast North Carolina greenhouse. You've changed your dates from Mother's Day to June, JC. Is this greenhouse free-standing or part of a larger, heated building? Is there adequate ventilation?

I think you'll need to take a good guess about what the growing temperatures will be throughout the time the plants will be in there. Decide when you want a crop (early-May, mid-May or June) and think about the possibility of moving the plants outside when warm weather arrives.

Steve

 

[Reinbeau]

Another thing about Calendulas - they're the Herb of the Year for 2008! Might be a good sales tool/reference. Mine come back year after year in the garden from last year's seeds. Grow them cool and I don't think you'll have any problem. I grew them from seed last year (I wanted to try a new variety) in my cellar under grow lights and had lovely plants to set out.

 

[jc12551]

I set up a temp. probe to record temps today. The greenhouse was shut up and it was HOT in there.

I am thinking to start with leaf lettuce and radishes, zinnias and marigolds. I need to get it cleaned out, there is a canoe and scrap lumber (hmmm I am building a coop) along with a dozen fish tanks.

I was checking out the equipment installed in the greenhouse and I think it may be heated. There is a unit connected to a propane tank.

My landlord/colleague and I are going to dig compost off one of his properties on MLK since we are off work.

I am so excited. I feel a new club forming: The Greenhouse Club. Ok, it needs a better name, but maybe it could be 4-H supported like our GIS club. I am getting all tingly thinking about it.

 

[digitS']

To give you an idea of varying temperatures in a greenhouse:

My "sunshed" has an insulated roof and north wall. The entire south wall is a single sheet of plastic. It is 9' x 20' and unheated until early March.

The sun appeared today !! After a fairly warm overnight temp of 28F, the morning fog burned off about 10 AM and we had warm sunshine for a couple hours. The outdoor temperature climbed to 41 by noon!

The minimum reading on the thermometer's history mode says that it was 30 in the greenhouse overnight. It was 61 at noon!

By 2 PM the sun had been hidden behind clouds for about an hour and the greenhouse had dropped back to 45 - about where it is right now. It is now (3:20) getting close to dark but the outdoor temperature is still a fairly warm 38.

The sun is very low right now since I'm so far north. (Did you know that at 48 North Latitude, I'm north of Maine?) The sun was only out for about 2 hours but the greenhouse was 20 warmer than the outdoor temperature. If it had been out for 4 hours it wouldn't have surprised me if the greenhouse would have been close to 80!!

All this is fine but come March and April and I'll need to be very observant because there's no more automation in there than one fan (and the furnace) on a thermostat. It can be 45 outside and 95 and cookin' in the greenhouse.

Steve

 

[patandchickens]

if in fact it does have propane heat, a) I would betcha it has (or used to have) some sort of automatic vent control mechanism, look into it so you don't roast your plants; and b) please do not even consider trying a propane heater, especially an older one, without first installing a working carbon monoxide detector.

You could consider whitewashing or partly shading the top of the greenhouse to reduce peak temperatures... usually done only in summer, but might be something to consider if you don't have thermostatic venting after all.

(edited to add: another thing that will somewhat moderate temperatures would be having large masses of stone, cinderblock, or water in there - especially useful if it is not the biggest greenhouse in the world. The more thermal mass, the less it will cool off during the night and (probably more important) the more slowly it will heat up during daytime. Putting flats of seedlings directly onto a cement or brick or gravel floor (rather than up on benches) will also help keep them cooler at day, although cool air will also puddle there at night)


Pat, whose parents' orchid house (since childhood) permanently cured her of any desire to operate any sort of heated greenhouse

 

[jc12551]

We need to get all the parts checked out. The AG program was moved off campus so they can't use their greenhouse, but before that it was routinely used (before my time here). I think there is some automation, there were several switches and dials, but the power is turned off at the breaker currently. I don't know a whole lot about running a greenhouse, that is why I have all these questions! I don't have a science classroom and therefore have no place to raise a lot of plants like I used to and would like to engage this level of students in something worthwhile.

 

[patandchickens]

Hey, how about coleus? Either from seed or cuttings (or both!). Nice and brightly colored, fast, easy as long as you keep them damp, you could shade them in the greenhouse.

Pat

 

[jc12551]

Never grown coleus from seed. I need some for the front of my house and I guess my students could grow them. hmm...keep the ideas coming!

 

[silkiechicken]

Ours was called the greenhouse club. LOL