Greenhouses | Page 9 of 14

Customer warmly endorses Polydome Garden Tunnel

Dear Polydome,

In an age when many people only contact manufacturers in order to complain when something goes wrong, we thought you might like to know how well our hobby tunnel, erected in 2006, withstood the storms of last winter.

On February 12th, the ferocity of the wind on our exposed site near Arklow demolished all our fencing panels, ripped the asphalt covering from the garden shed and smashed several panes of greenhouse glass. Our Polydome tunnel alone defied the elements, emerging at the end of it all as solidly anchored as ever, with all its polythene cover intact, proof if we ever needed it of its superior construction and the excellence of the materials you use.

Congratulations – and heartfelt thanks!

Patricia and Roger

Controlling aphids, good advice from our gardening blogger Peter Whyte

It’s handy to be able to keep tender plants and grow salad crops in the greenhouse over the winter. Protected from the worst of the frost, they survive the cold so much better than outside. But aphids overwinter better in a greenhouse too. Commonly called greenfly, the many different species come in all colours and some, like woolly apple aphid and lettuce root aphid, are covered in white waxy ‘wool’ to deter predators.

Aphids are weak fliers, and easily killed by cold or washed away by rain. Their only hope of survival outdoors is to lay eggs to hatch out in spring, but in a warmer, drier and wind-free greenhouse the adults can live all winter. When the sap starts to rise in your precious plants they give birth to live young which are bearing young themselves in a few days, so their numbers snowball quickly.

What can you do? Various aphid predators can be bought for releasing into a greenhouse, but most take time to build up and reduce aphid numbers to an acceptable level. For best results use them exactly as recommended. You could rescue adult ladybirds from winter prunings and cleanups, and leave them on the plants in your greenhouse. Sprays come and go: check with your local garden shop or centre to see what’s currently available, and follow the instructions carefully. Some spray very dilute washing-up liquid weekly.

If you want organic remedies try Pyrethrum or sprays based on fatty acids, or on plant or fish oils such as rapeseed oil. Hose down plants with water to dislodge aphids, or squish them on the shoot tips between finger and thumb, or brush them off with a soft brush. Grow root aphid-resistant lettuce varieties. Tagetes grown between other plants can deter aphids.

The morning after (by our blogging horticulturalist Peter Whyte)

The morning after

The morning after the storm of the 12^th of February, the lawn was littered with broken glass. Our glasshouse had come through many storms unscathed, but not this one. It was a testament to its sturdiness that I found only one pane broken, and soon picked up the pieces with gloved hands for bringing to the recycling centre. More bad weather was forecast, so the glass needed to be replaced as soon as possible.

I rang Polydome. “Which kind of glass do you have, safety or horticultural?” asked June Pyle. After all these years I wasn’t sure. “No problem” she said, “I can check it on the computer.” Seconds later, she said “You bought the glasshouse in 2004, you have horticultural glass, the pane you need is 61 by 61 centimetres and we have it in stock.”

At Polydome the staff was busy tidying up after the storm, but within minutes I was driving home again with the glass laid flat in the boot. Glazing clips were no problem as the greenhouse had been supplied with plenty of extra ones. Fitting the glass needed care as glass is very brittle in cold weather, so I took it slowly and carefully and all was well. By all accounts many people with lighter-built greenhouses and in stormier areas were not so lucky.

Preventing snow damage (our blog by horticulturalist Peter Whyte)

The opera isn’t over until the fat lady has sung, and winter isn’t over until danger of heavy snow is well past. The problem with snow is twofold: it is so heavy when it lies that it can damage or distort greenhouses, and more damage can be done by trying to remove it.

Snow is light in thin layers, but as it builds up its weight increases quickly. Ten or twelve centimetres of snow can melt down to one centimetre of water which doesn’t sound much, but over the area of a roof it’s enough weight to do damage. It’s especially a problem if the wind drives it on to one side of the roof in a lopsided pile, as the uneven weight distribution can bend the framework over sideways.

Taking it off makes sense, but must be done carefully. All cladding, be it glass or plastic film, is more brittle when cold. It’s all too easy to break a pane of glass by touching it with a metal implement or puncture polythene cladding with a sharp object. Use a plastic or rubber-tipped shovel or a soft brush, or on polythene tunnels a strip of cloth or soft rope sawn gently back and forth across the top.

Clear a glasshouse in the same way as installing the glass in a new one. Don’t do all one side and then the other, as the weight can distort the frame. Remove a small amount of snow from each side alternately, and work from one end to the other. Wear gloves over your coat cuffs, or you might get your arms soaked in melting snow!

Overwintering your plants

In for the winter

Have you tender potted plants in your greenhouse for the winter?

You can’t just walk away from them until it’s time to put them out again. If you do, their survival depends on luck and you might not be lucky. You need to check them occasionally, and deal with any problems that arise.

As mentioned last month you should water plants under cover sparingly in the winter, but that doesn’t mean no water – it just means less. Plants still die of thirst in winter: they just take a bit longer to die. Water containers only if the surface of the compost is dry and no particles of compost stick to your fingertip. There’s no need to soak all the compost in a container, and keep the leaves and stems of the plants dry to prevent rotting. Plants that are flowering or actively growing need more water than dormant plants.

Water early in the day to leave maximum time for surfaces to dry off before dark. This helps to control grey mould and other fungus diseases, which thrive best in damp conditions. Removing dead leaves helps too.

The theory of watering sparingly is to keep tender plants slightly dehydrated. This concentrates their cell sap and lowers its freezing point, hopefully below the temperature of the air. If the sap in a cell froze the ice crystals forming in it would expand and burst the cell, so it could no longer function properly. The problem is that there’s a narrow margin between mild dehydration and permanent (irreversible) wilting. So check your plants often, but water little and seldom!

Check plants for whitefly, aphids and slugs, and deal with them promptly if they appear.

Peter Whyte gives tips on growing winter greens

Winter greens

You could pull out the last of your summer crops from your greenhouse, clean it up for the winter and close it until spring. But why not have it produce fresh green salads for you all winter? If you didn’t sow any leaf greens in recent weeks you can still sow turnip seed in early November and expect the soil to be still warm enough for some growth. It will grow slower than would September-sown crops but still be worthwhile.

Failing that, you can plant roots of turnip and beetroot in pots or the greenhouse soil and let them sprout leaves as if it were next spring. The leaves might not be as good eating as the seedling ones but will be better than nothing. The roots may need some frost to trigger this re-growth. Watch out for slugs.

Chicory has traditionally been grown for forcing in winter. Dig up straight roots about 2cm thick, cut the leaves back to about 2cm high and shorten the roots to about 15cm. Store them flat in sand in a cool shed. Every few weeks, plant a half-dozen or so roots upright and tight together in a medium pot of damp compost, placing it in a shady part of the glasshouse and covering over the top with an upturned pot (cover the drainage holes) to exclude light. Darkness makes the emerging leaves paler and less bitter. Cut them for eating when about 15cm high.

Rhubarb roots can be forced too. Dig up crowns and leave them exposed to frost. Then pack them tightly into a container with old compost, leaving them upright. Put it in a shady part of the greenhouse covered with black plastic. Harvest the sticks when still small and dump the exhausted roots afterwards.

Growhouse prices are due to increase by 10%

Growhouse (Western Red Cedar Greenhouses) have just announced prices are going to be increased by 10% from the 1st of November. If you were thinking of getting one now would be a good time to order to save yourself some money. Click here to go to our Growhouse page: https://www.polydome.ie/subcategories.php?maincatid=3&catid=79

There is a second good reason for buying a Growhouse now – they have a special offer running that is a free unit of staging will come with each Greenhouse ordered before the end of October.

Photo Competition Winner

Many thanks to everyone who contributed photos in our recent competition for Glasshouse and Polytunnel customers. We had such a good response that our email system at one point was unable to cope under the weight of all the pictures! All photos were greatly appreciated and it really showed the enthusiasm that people have for growing which is fantastic and in fact inspiring. The competition is now closed and we will be reviewing the photos over the next week or two to select a winner in a couple of categories (next time we will put the cart after the horse and tell you what the categories are before the competition!). Many thanks, Jonathan Pyle, Director.

Back from the Ploughing

We are back from the National Ploughing Championships which was the best attended show ever with numbers attending topping 220,000.
We ran out of brochures as mentioned in my last blog and I have to give a great big thanks to The Print Factory in Birr for their outstanding customer service. At 4pm or so on the first day I asked them for more brochures as it was clear we would not have enough for the show, they printed them that night and I facilitated me to collect them at 5.30 am. As a result several thousand people have our nice new Garden Polytunnel price list, so a great big Thank You to The Print Factory – who you can call on 057 913 3119.

First day of National Ploughing Championships

Fantastic first day at the National Ploughing Championships. We nearly ran out of brochures allocated for the whole show. Great upbeat event with everyone in a positive mood. A lot of interest in our Polytunnels for both gardening and farming (livestock housing) with good feedback, people can see the quality and strength of our Tunnels on display.