Tips for Growing Vegetables in a Greenhouse

[Species-8472]

Hello to the moderators and members of this site. I think its great so far with a nice all-round mass of info and people willing to exchange info. Its good to see.

So, straight to it.. it is my goal to build quite a large Greenhouse completly for the purpose of growing vegetables. My only real concern so far amidst all my planning is.. Do I have to keep with the seasons in general for planting and harvesting..? Or, because I would have full control over the growing environment can I totally disregard the majority of planting & harvesting guidelines..?

I couldnt bear to think that my produce would be limited to certain times of the year. I like the idea of continuous controlled year-round supply regardless of how much work it takes.

Also now that I'm here, are there any other Irish on this forum..?

Great job to all the mods and controbutors here.. I hope I can submit the same in the future..

[Grey]

I wish I had a greenhouse!

As far as I know - if you have a greenhouse, you can grow just about anything anytime. That's the beauty of it! You'll be the envy of the neighborhood.

I'm originally from Florida, which is almost a natural greenhouse complete with humidity, and I could grow tomatoes right up to late November when the weather would turn just chill enough to slow them down. Since the winters were mild, I could grow broccoli, cauliflower, collards, all types of lettuce and cabbage all winter long, and both in the spring and early fall I could grow corn (If I could keep the squirrels off it), carrots, tomatoes, eggplant, peppers, peas and beans.

Welcome to the forum!

[Species-8472]

Thanks for the reply,

Yea we get pretty stormy winters here.. High winds, heavy rains, definately cold (avg temp -2 to 2 degree Celcius) for most of the late Autumn & Winter days and the first 2 months of spring before temperatures rise to about 6 to 10 Celcius coming into April with the odd day of 10+ sunshine.

I was hoping for an all-year-round set-up.. My only concern was if the plants followed a biological time frame.. So you reckon they don't..? Its no different planting my summer veg in a controlled winter greenhouse..?

[Grey]

I've always wondered if plants have a biological timetable, but with what I could grow at abnormal times in FL, then think of folks in New Zeland where their winter is our summer...

I can't say I know but surely other folks on this forum will. My thought is that seeds don't know what month it is, only that the soil is warm enough to sprout and the daylight hours are long enough to encourage growth.

Oh and hey - everyone says how cold Ireland is but -2C isn't that bad! Would American immigrants be welcome?

[opabinia51]

If your greenhouse is climate controlled, then you don't have to worry about that part of the food growing element but with certain fruits and vegetables a particular pollinator is needed or the plants need to be hand pollinated in order to get the particular fruit or vegetable.

But, there is really no need to spend the $$$$ to build an enormously expensvie greenhouse nor spend all the time needed to pollinate your plants.

You can simply garden year round using plants that are suited for the changing climates. Brassicas and other plants are winter hardy and when seeded in mid to late August will provide you with greens all winter long. There are also winter varieties of Lettuce.

[Species-8472]

Thanks for the info guys. I've gathered as much info and knowledge as I can about most of the aspects of getting a large home-made greenhouse up and running. The more I read, the more I think about corners I can cut to make the environment operate more efficiently and my pocket work with me more efficiently

The only inconvenient aspect is insulation so I have decided to allocate a 1 - 2 meter hallway area entering 1 end of the greenhouse. I do this because the way I see it, most of my heat is going to escape through the doors so if I build to include 2 doors at 1 end then I can create a moveable insulation "Blanket" on the outside of the inner door and the inside of the outer door. So the hallway is the doorway for my insulation. I figure I use the excess space in the hallway for tools, charts and other items that I don't need cluttering my grow space.

As for Irish weather Grey.. Its not so bad. We get more often than not (1 day in every 8 or so) when the weather is below the averages I stated but, I've been to Germany in -17 celcius and lemmie tell ya, It was a tough day in the greenhouse that day. The snow had taken out at least 20 of the glass panels so all temperature was as good as outdoor weather. Hahaha we had a hell of a time transplanting.. cant believe our boss even allowed it. I think he was trying to get them all sent to another hall though where the temp was up nearer 1 or 3 degrees (and these were just plants not veg)

It was amazing to see how a profitable-(supposedly) greenhouse business fell apart with 2 - 3 weeks of sub zero's.. Took em a lot longer than 2 - 3 to get back on track..

Thanks again for the info guys

Damon

[The Helpful Gardener]

Hi Damon,

While the greenhouse would be welcome for crops like tomatoes and such, you'll find that whatevere space you think is plenty is never enough.
Think about cold weather crops for outside (The crucifers) and then those warm weather things for indoors ('maters, basil and such). Heating costs being what they are (and god help us all, where they're going) you will not want to be heating a whole lot of space; always the big unseen for most novices...


Scott

[Species-8472]

Thanks Scot. However my plans of course include underground & overground heating cables as I DO intend on generating a part time income from this interest.
If my books stay out of the red, I'm there dude

I have a solid fuel cooker in my house so running some pipes outside isnt gonna be too much trouble and its a pretty efficient system as having it lighting during the winter will; keep the house warm, provide hot running water all day, provide something to cook meals in/on and now.. hopefully, heat a greenhouse hopefully lol. I'm lucky to be trading a bigger bill for more regular maintenance (If it works full-time). But I think its a fair trade, the way resources are priced here too!

Electric alone jumped many a percent from this time last year to now. Up in stages of 6% then 8 then another 6 and then a 12% I think if I'm not mistaken. And thats JUST Electricity! I'm not sure about the rest of the resourses as they don't affect me (yet) Its expensive enough as it is to live in Ireland.

[The Helpful Gardener]

I'd heard, although we are finally on our way to matching your petrol prices...

[DAnderson]

Damon, I am also thinking about building a greenhouse (have always wanted one), but will build a small one this fall to try it out. I'm afraid of spending alot of $$ on something I may be disappointed with. Will try to start with tomatoes, peppers & cucumbers. I know I will regret not having more space, but think this is the safest route for me. My husband will end up with the building project, so I don't want him spending alot of time on something I'm not sure I'll use.
Sounds like you have some greenhouse experience. What were you growing in greenhouses before?

[Species-8472]

I'm afraid my Veggie experience in greenhouses is pretty much "nil/nothing".. However I have worked in the biggest Greenhouses/producers in Europe so I have plenty of general knowledge which is easy to build on with logic.

You say you are cautious about spending too much money on a greenhouse.. My reccomendation is to build [url]https://www.jcmga.org/greenhouse.html[/url] this one.

Its cheap and easy to construct. The only thing is it's not the most effecient on insulation but you can double up on certain areas to increase its stability.

I'm designing a clever contraption which uses Hydro Power [url]https://www.canhydropower.org/hydro_e/p_hyd_b.htm[/url]

If my idea works (which I know it will) then I'll pass on the info. The reality of the idea is to heat a good sized greenhouse in the winter using the same amount of electricity as you would use to power a Child's "Meccano" set (light-metal construction set for kids).

Write back for queries

Damon

[The Helpful Gardener]

What about passive sources Damon?

[Species-8472]

Here are my Scientific Sources for Passive Energy research

Hydro Energy

[url]https://www.ucsusa.org/clean_energy/renewable_energy_basics/how-hydroelectric-energy-works.html[/url]

Wind Energy

[url]https://www.ucsusa.org/clean_energy/renewable_energy_basics/how-wind-energy-works.html[/url]

Solar Energy

[url]https://www.ucsusa.org/clean_energy/renewable_energy_basics/how-solar-energy-works.html[/url]

Geothermal Energy

[url]https://www.ucsusa.org/clean_energy/renewable_energy_basics/offmen-how-geothermal-energy-works.html[/url]

Biomass Energy

[url]https://www.ucsusa.org/clean_energy/renewable_energy_basics/offmen-how-biomass-energy-works.html[/url]

The two that appeal to me the most from this list are Hydro Energy and Wind Energy. This is mainly because these two types can be created the cheapest/easiest "for me".

I have drawn up some plans for a small wind tower to be positioned on my shed roof in the future but they will remain plans until I complete the Hydro project.

How about you..? Do you Utilize passive energy..?

[hugh]

I used to live in Ireland, admittedly the North. The problem is daylight, as you know it is in short supply particuarly in the winter. Unless you go to the expense of special lighting, you will have to compromise.

There are varieties of certain (salad) vegetables which will grow in the winter - you need to check seed catelogues. But in general you will find that the benefit of the green house will give you is a head start in terms of seasonal crops.

Also in Ireland make sure you have good ventilation, you know about the damp air in Ireland. You might want to incorportate a fan into the system.

[Species-8472]

Tx hugh..

Yea I've just recently installed the fan because of the dampness.. all is in check though and I'm starting to see good growth on all plants

[hugh]

In Ireland - well at least in the North - bedding plants and veg for planting out are behind because of what is jokingly called the spring in those parts. This can be a major advantage of a green house.

Now if you want to make a bit of pocket money you can grow these for yourself and sell the inevitable surplus. This also has the advantge of clearing out the space for the summer crops e.g. tomaotoes, cucumbers etc.

By the way you do need a gap in the growing schedule to sterilise the soil and the total green house. Because of the humid conditions in Ireland, it is essential once a year to make sure you are totally clear and 100% sterilised. You may get away with it the first year but subsequent years it is essential.

[The Helpful Gardener]

A good tip there, Hugh. Hygiene and biological control are the cornerstone of good greenhouse management.

While sunlight remains the best sterilant I know, what other measures are you taking? Pests in particular can be an issue; The "Q Strain" of whitefly is tearing up the bedding plant community here due to it's pesticide resistance. Are you planning on chemical or biological controls?

HG

[hugh]

An old fashioned steriliser for green houses in Ireland is Jeyes Fluid. In fact it is usefull product to have around for general pest control. It is non systemic. It is the only product I found that would 100% deter slugs.

I used it as a preventative, if it was not effective then I would use something more specific.

But make surre you get the dosage right. It is totally diffferent for sterilising and pest control. My wife once mixed up the two and sterilised a few rows of vegetables, they died pronto.

[The Helpful Gardener]

What's the active ingredient? (if yopu and Mr. Jeyes don't mind me asking... )

HG