Category: Greenhouses

It’s very disheartening to pick a lovely ripe tomato in your greenhouse and discover the bottom is all hard, black and sunken. That’s Blossom-end rot. It can also affect melons, squash, peppers, and aubergines. It’s not an infectious disease but a physiological disorder caused by lack of calcium in the plant. Calcium is needed to build the cell walls of the growing tomatoes, but if there’s not enough coming in from the soil the cells will be too weak and burst with the pressure of water coming up from below.

Tomato plants can’t always get enough calcium, especially when growing fast. Soils low in lime may not supply calcium as fast as the plant needs it. Roots cannot absorb enough calcium from cold or dry soil, even if it’s there. Letting soil get too dry and then watering heavily will cause a rush of water up the plant and burst the weakest cells – the ones farthest from the supply of calcium.

Add lime to the soil if a test-kit shows it’s needed. Dig in compost or other organic matter to borders to hold more water in the soil. Don’t plant crops into cold soil or grow-bags. Don’t use too much high-nitrate fertiliser such as chicken manure: it encourages soft rapid growth more prone to this problem. Fertilisers lower in nitrogen and higher in phosphate (which encourages root growth) and potash (which encourages stronger, harder growth and fruit ripening) such as ‘Tomato feed’ are best. Water well and regularly, before the soil gets too dry. Mulch the plants with compost to keep the soil moist. Avoid damaging any roots by cultivating near plants.

So the problem is easily cured. And although the affected fruit look unappetising, you can cut out the bad bits and use the rest for cooking.

Whitefly is a serious pest of greenhouse crops.  It can severely damage plants and is hard to control.  The adult flies are covered in a protective layer of white wax.  They fly up in clouds from plants when disturbed.  They suck plant sap, spreading plant viruses and depositing sticky honeydew which attracts black sooty moulds that are hard to wash off leaves and fruits.  They lay eggs on the undersides of the leaves which develop into greenish scales, each with a grub inside.

The colour yellow attracts whiteflies, so you can hang up sticky yellow cards to catch them and detect their arrival or reduce their numbers. You can shake plants and catch them with a hand-held vacuum cleaner when they take off: avoid damaging the leaves.  Planting French marigolds among crops may help.  The parasitic wasp Encarsia Formosa can work well in large greenhouses when conditions are right.

Check under the leaves of new plants carefully before putting them in your greenhouse: plunging their tops into a bucket of water will kill many of the adults but not their scales.  Burn or bury dead or badly infested leaves.  Keep the greenhouse and its surrounds clear of plants over the winter to remove host plants and starve them out.  Sprays based on pyrethrum, neem oil or insecticidal soap have been used formerly, but with changes in pesticide laws may not now be available.  Whiteflies can quickly develop resistance to a chemical, so if spraying change the chemical often.

Eden Greenhouses are offering free ridge cresting, a free louvre and a free automatic roof vent opener for orders placed at the show.  This is in addition to our special offer currently running of 10% off our Eden Price List (Greenhouses only).

We are off to set up for the Bloom Show today which starts on Thursday and runs until and including Monday.

Our stand is in the same spot as last year, OR42 and we will be showing two Greenhouses, a Janssens Victorian SL which is incredibly strong and one of the new Eden Greenhouses with the revolutionary zero threshold door entrance design.

Special offers for orders placed during the show for Janssens Greenhouses include free automatic vent openers for all roof vents and a preferential price for construction.

There will be a special offer for Eden, to be advised later.  The main thing is not to miss seeing the new design as it incorporates radical improvements – the zero door threshold which is amazing, wider gutters and serious downpipes for rainwater collection and the larger gutters add considerably to the strength of the Greenhouse.  In addition it has very neat capping to secure the glass much better than with spring wire clips and it also enhances the appearance.  There are also special clips at the eaves which by allowing air movement prevents algae growing where it can otherwise.

One of our suppliers has informed us that their cost price of polymer (the raw material for polythene) has been steeply rising recently for a variety of global reasons.  The result is that its cost has ‘rocketed’ to unprecedented levels – it is not currently more expensive than it has ever been before they say.  This will have a knock on effect on future deliveries.  We thankfully have quite a lot of polythene in stock so can maintain our price for the summer and possibly the autumn.  If you think you might want polythene now is the time to buy to avoid the impending price increases that will affect everyone in the industry.