Solar Greenhouse Fans

[ghexton]

Hello All,

I'm due to erect my greenhouse this weekend. I have been speaking with my neighbour and they had green house in very similar location and complained of toms getting blight, as its a sheltered area and they many not get much air flow.

I'm keen to stay ahead of the game and try get some decent air flow.
I was thinking getting solar fan?

Is there any recommendations from any one.
ive seen couple of amazon ranging from �10 smaller ones to a �90 20w one.
Ideas all welcome please.

Thanks.
G

[quanglewangle]

See my thread Fan to lessen chance of botrytis? in Undercover Ops

https://www.growfruitandveg.co.uk/gr...is_100698.html


My problem with solar powered fans is that they won't start first thing in the morning, at dew-forming time, when they are needed most.

Folks on here seem to favor alternatives to fans such watering methods and lower planting density. But fans are used a lot in commercial greenhouses and I think it is worth paying some attention to folks with money in the game.

[greenishfing]

I agree. Blight spreads from plant to plant - on the breeze. Air flow will not stop it. Good ventilation however is essential to prevent botrytis. The absolutely best thing you can do is not to overcrowd your greenhouse.

[quanglewangle]

Agree about not *over* crowding but the greenhouse is an asset and heating is a fixed cost. The space needs to be worked as hard as possible and I think a fan will helo do this. .

[veggiechicken]

Folks on here seem to favor alternatives to fans such watering methods and lower planting density. But fans are used a lot in commercial greenhouses and I think it is worth paying some attention to folks with money in the game.

Commercial growers in their massive GHs, are out to make a profit and prepared to invest cash in doing - they are miles away from the home grower with an 8X6 GH. No comparison whatsoever.

Increasing ventilation by opening windows and doors, watering carefully and spacing the plants works in these situations. The main thing is to have plenty of windows that open - and to open them!

[veggiechicken]

Agree about not *over* crowding but the greenhouse is an asset and heating is a fixed cost. The space needs to be worked as hard as possible and I think a fan will helo do this. .

Heating isn't a fixed cost - its a zero cost for most of us because it isn't necessary.

[quanglewangle]

Can I ask how long you have had a greenhouse and how long you have been growing tomatoes?

A year and a yesr, which is why a look towards commercial practice to get up to speed.

[quanglewangle]

Growing commercially is very different!
You obviously had issues last year...How big is your greenhouse and how many plants did you put in it. Regardless of any ventilation if your plants are too crammed you will likely get botrytis.

Hardly any really. That's not the issue. I am quite interested in modelling commercial greenhouse. Just waiting for La Boheme to start so need to shut off phone to avoid hard stares.

[veggiechicken]

Che gelida manina................

[veggiechicken]

QW, you're a gadgets man.

Me, I'm a technophobic chicken who's been growing in a GH for 45+ years and won't be changing her ways in the next 45 years.

Each to their own - Good luck.

[SarrissUK]

I'm a bit of a gadget geek too, and I have a couple of little fans that can clip on to the metal frame and draw in fresh air from the window on the side that isn't getting the direct sun. I have no idea if it helps, but it makes me feel like I'm doing something, compared to doing nothing other than opening doors and windows.

However, I agree with the other posters - I reckon it's not blight, it's botrytis, and I had some of that last year. My greenhouse was full to the brim, and it's no bloody wonder I had damp problems.

What seemed to work best was that I picked off almost all the leaves off the plants. It was late in the season anyway, and once I had done that, air flow improved dramatically, and I didn't have any more problems after that. And I got two arms full of leaves for the compost heap

[quanglewangle]

Fans for circulation rather than ventilation

I am installing a fan for circulation rather than ventilation. I have no problem with the later - a small greenhouse and a big vent and when needed opening the door takes care of that.

Circulation is different. There are times when different parts of the space in the greenhouse are at widely different humidity levels and sometimes this occurs when you don't want to ventilate - perhaps it is cold outside or there no breeze anyway.

It is possible to have an optimum RH, say 75% but will differ depending on what you are growing, registered in an open part of the greenhouse but this doesn't mean it is not much higher in among foliage, especially on the underside of leaves, or much lower on dry sunlit compost. What is needed then is to stir the air up.

Of course the cultural methods given in this thread: lower plant density; ventilation; watering at, or close to or even beneath, ground level; and careful timing of watering will all help. I am not dissing these techniques: It's just that a fan will help even more.

[Mamzie]

I think they possibly got botrytis not blight?

That's often due to squeezing too many plants in. If you space your plants out with a good distance apart, keep your vents open and ensure you water into the ground and not the plants - I water into milk bottles sunk into the ground at regular intervals - keeps humidity down. I believe you have a better chance of them staying healthy right up until the frosts.

Sorry, I know nothing about fans...


Good info on botrytis here :

https://www.rhs.org.uk/advice/profile?pid=165

My mystery is solved - thank you Scarlet and co on this thread, I must have had botrytis not blight last 2 years. I know I overcrowd as find it very hard to discard any plants that are extras, plus by end of summer mine tend to loop de loop around the top of greenhouse. I will plan better this year now. I grow in pots in large containers for watering.

Does the disease live on pots please?

[Mamzie]

Ty, I water from the bottom as use large containers under the pots and the roots tend to grow into them.

Glad to finally put a finger on the problem through x

[ghexton]

GH Planning and Overcrowding

Hello,

Again thank you for all the advice. Well when you ask one question it leads you to another area, great i love it! feel like I'm learning here.

I will probs invest in few auto GH window openers then instead of solar fans.

So onto my next questions which i had already sort of thought about.Grow space planning.

I'm looking to grow for two adults and 1 baba.
GH is 6x10 Polycarb on gravel base - grow bag and pots if that helps
https://www.summergardenbuildings.co...-30201017.html

Cucumber - Start 8 seeds pick 6 plants in GH
Melon- Start 6 seeds pick 4 plants in GH
Chilli- Start mix 6 seeds grow 4 Plants in GH
Tomato- Start mix 12 seeds grow 8 Plants in GH
Peppers- Start mix 12 seeds grow 8 Plants in GH

Is this to much or to little?
Any other plants i should think about adding?

Full list of the seeds I plan to propagate below.
https://ibb.co/RDYrhxj

thanks
G