New greenhouse no knowledge?

Flowers, Trees, Lawns, Infrastructures, Maintenance & anything else!
Post Reply
pecker
Lively Laner
Posts: 45
Joined: 29 Jul 2008, 15:59

New greenhouse no knowledge?

Post by pecker »

I've recently bought a 10x8 greenhouse and I've started to grow cucumbers and tomatoes which appear to be growing nicely. I have now realised that I am in the dark with regards to keeping the correct temperature and which crops are best to grow in it, also, should I buy a greenhouse heater, thermometer or can you suggest anything else that may help me to grow more and better food.

I look forward to hearing from you,
User avatar
lancashire lass
Legendary Laner
Posts: 6528
Joined: 28 Jun 2007, 15:17

Re: New greenhouse no knowledge?

Post by lancashire lass »

oh wow, a 10 x 8 greenhouse - very nice 8) Bigger size greenhouses are usually better than smaller ones for several reasons - not only do you get to grow lots of stuff which is the most obvious, but the temperature fluctuations are gradual.

Plants like tomatoes, chillies, peppers and cucumbers respond well to warm temperatures, but don't like being overcooked. Ventilation is essential, especially on hot sunny days - temperatures above 40oC (and closed greenhouses can get much higher than that in full sun in summer) should be avoided. Leave the door wide open if you have to. A thermometer would be useful, but not necessary - stand in a hot greenhouse for just 5 minutes and you'll know it is far too hot for plants as well!

Because temperatures are higher than outdoors, plants will use up a lot of water. When growing fruiting crops like tomatoes and peppers, the soil should never go dry when they are in flower/setting fruit or you risk blossom end rot on the fruit (black ugly patch) Take care not to overwater either - you don't want the roots to be sitting permanently in water. During very hot days you might find some plants clearly wilting and yet you know the soil is moist - this is only temporary and basically the plants are losing more water than their roots can cope with. Ideally you might want to then consider shading - the sun through clear glass will raise temperatures quickly. In summer, the sun's strength can also scorch plants. You can buy a sort of white wash which you paint on the outside (do check with the greenhouse instructions first especially if it has polycarbonate glazing), or a sort of netting which you hang over the greenhouse to provide some shade/diffuse light.

Humidity is also another factor to watch out for - tomatoes don't tolerate humidity too well and can succumb to moulds, so another reason why good ventilation is essential. However, some other plants such as chilli, peppers, cucumbers need higher humidity - in dry conditions, they can get infested with pests such as spider mite, so spray mist the plants morning & evening or put water on the floor so that it evaporates and increases humidity in the greenhouse. As you can see, it can then be a bit of a juggle when growing different crops in the same greenhouse - perhaps you could position your tomatoes nearer the door where they'll benefit while it is open.

Spacing between plants - quite a hot debate among many gardeners. Because greenhouses are sheltered, plants tend to grow rapidly and spread out. If you have too many plants close together, pests and diseases are likely to spread rapidly more so in a greenhouse than outdoors. Personally I think I have learned from experience that plants do better if given a lot more room and this also improves ventilation.

Hygiene - following on from above, it is important to be diligent and keep on top of anything that does not look right. If you see mould, remove it and improve ventilation. Watch out for any pests such as aphids or spider mite - if you have an infestation, it will go through the greenhouse like wild fire as they will have no natural enemies to prey on them

Insects - essential for pollinating some crops, but some insects are also pests that lay their eggs and the larvae then munch through the developing fruit (nothing worse than seeing a hole in a green tomato) You can pollinate your tomatoes and chillies/peppers by shaking the flowers. Greenhouse cucumbers tend to be all female, so pollination is not necessary (you would need to read up on the variety which are growing to be sure) Obviously if you have the vents and door open, it's an invitation but you could construct a screen to hang on the door rail (a wooden frame with fine netting stapled to it with a couple of hook screws on the top) and this should stop some pests from getting into the greenhouse.

Heaters - there's no need for heaters from about mid-spring to autumn except if there is a particularly bad frost forecast and you have tender plants. The greenhouse will provide shelter from a light overnight frost. Over winter - well, heaters can be expensive to run, and paraffin based ones also give off a lot of water vapour and fumes and probably not ideal for crops. I don't tend to grow much in the greenhouse over winter (maybe some lettuce, a few broad beans and peas that are hardy anyway, and they are protected from the snow and ice in the greenhouse to plant out in spring when they will be well ahead of spring sown stuff) so I don't use heaters. You have to bear in mind that in winter, the sun's strength is very poor - growing fruiting crops in winter would need additional lighting too ... so it's not really something the average person would doing.
User avatar
Annie
Project Hedgehog Leader
Posts: 10383
Joined: 01 Aug 2010, 15:45
Gender: Female
Location: lennoxtown North of Glasgow

Re: New greenhouse no knowledge?

Post by Annie »

Wow shes good isnt she ? )t'
L.L. {hug}
It will be alright in the end , if its not alright, it isn't the end .
Quote from the proprietor of the The best exotic Marigold Hotel for the elderly and beautiful
pecker
Lively Laner
Posts: 45
Joined: 29 Jul 2008, 15:59

Re: New greenhouse no knowledge?

Post by pecker »

That's fantastic, thanks for sharing your obviously great knowledge. )t'
pecker
Lively Laner
Posts: 45
Joined: 29 Jul 2008, 15:59

Re: New greenhouse no knowledge?

Post by pecker »

Alex. And Annie, you're not wrong! :-D
Post Reply