A sweet idea for Greenhouse growing (Sweet Potato that is)

Sweet potatoes are related to morning glory and not ordinary potatoes. It’s possible and fun to grow your own. Plants are usually raised from ‘slips’ taken from sprouting tubers. You can sometimes buy them online or in a garden centre; ‘Beauregarde’ and ‘Georgia Jet’ (with orange flesh) and ‘T65’ (white flesh) are suitable varieties. ‘O’Henry’ produces tubers close to its base and is good for container growing.
Bought tubers can be from varieties less suitable for Irish conditions, but you can still get a small crop from their shoots. Organic tubers unsprayed with sprout inhibitor are best. Stand the tubers half-submerged in lukewarm water with their narrow ends down. Place them in a warm sunny spot to sprout, changing the water daily. Cut off the sprouts when they are about 15cm long. If still rootless, root them in warm water or cutting compost and plant when rooted. Soak bought-in slips overnight in lukewarm water before planting.
Plant them deeply (to encourage tubers to form at the nodes) in light, well-drained, fertile, neutral or acid soil in full sun. Always keep plants and tubers above 10°C/50°F. Give warmed water when needed, and feed weekly with tomato feed. Tie up the sprawling stems or they will root into the ground at the nodes. Green leaves can be eaten in salads or lightly cooked like spinach, but don’t take too many or you will reduce the tuber crop. Dig up the tubers after 3-4 months when the foliage turns yellow and dies back. Avoid damaging them as they bruise easily. Dry the roots in the sun for a few hours and then cure them for five days at 30-32°C / 85-90°F and 85-90% humidity. Store them above 10°C/50°F in good ventilation and either eat them soon or blanch and freeze them.

Sweet Potato

Preventing damage from snow

As the whole country is bracing itself for the ‘Beast from the East’ we would like to advise customers with Glasshouses that once it is safe to venture outside you should remove snow as it is surprisingly heavy and can collapse structures if allowed to build up excessively.

If you have an electric heater for use in Greenhouses (specially sealed for a wet environment) you could leave it running as the warmth may help to melt snow before it has a chance to build up. If you have a direct fired heater – e.g. a gas heater that works like a gas hob inside a metal cover, only leave it running if you can be positive that there is a fresh air supply to it that will not get blocked (otherwise it will burn up all the oxygen and produce carbon monoxide with potential disastrous consequences).

Any number of ways (such as soft bristled brushes, sheets, mop handles etc.) can be used to dislodge snow but whatever you choose try not to damage your powder coated frames or scratch the glass in the process.

It is also possible to prop the roof inside your Greenhouse as an extra precaution if you can lay your hands on suitable equipment and have the know how but of course this should be done before snow builds on your structure in case it could collapse while you are in there.

We hope that everyone will be safe and well which is the most important thing, your Greenhouse can always be replaced – and you may even have insurance to cover it, but of course it is not worth taking any risks to protect it.

Carrots for May

You can buy carrots in the shops almost any time, but nothing beats your own early carrots for flavour and juicy crunchiness, harvested just before eating in spring. Carrots sown in a tunnel or glasshouse in February are ready to eat about late May, well before any crop sown outdoors would be ready. In milder areas, seed can be sown in January for even earlier crops.
The traditional varieties such as ‘Amsterdam Forcing’ or ‘Early Nantes’ are as good as any for early sowing. Border soil for sowing carrots should be light, stone-free, without recently added manure or compost and above 5°C. Sow the seed thinly in drills about a centimetre deep and 20 cm apart. If the soil is very poor you could sow them in large pots of prepared compost or compost/soil mixture. Cover the drills or pots with fleece on cold nights to keep the soil as warm as possible: the warmer the soil the faster they germinate and grow. Protect the emerging seedlings from slugs, and as soon as they are big enough to handle thin them out to about five centimetres apart. Do not let the soil dry out, as it stalls growth and the carrots can split when watered again. If not eating harvested carrots right away, cut off the leaves to prevent them drying out and shrivelling the roots.

Delicious carrots

Newest addition to our display

Arcadia Plus Lean-to GlasshouseThe latest addition to our Greenhouse display area is this lovely Janssens Arcadia Plus Lean-to.  We configured this one to include Twin Wall Polycarbonate Glazing on the roof – which diffuses direct sunlight and helps retain heat, and we have clear toughened glass on the walls.  While perfect for growing plants this Greenhouse would also suit the increasing number of customers who want a room with a view in the Garden to relax and read a book and drink a glass of wine.  I’ll have to take another photo when we have the table and chairs and bottle of wine in it, but all in good time.

Merry Christmas

We wish all our customers and colleagues a lovely Christmas and all best wishes for the coming New Year.

May the road rise up to meet you, may the wind be ever at your back, may the sun shine warm upon your face and the rain fall softly on your fields.  And until we meet again may God hold you in the hollow of His hand.

Radishes – our blogging horticulturalist Peter Whyte extols its virtues

If radishes were harder to grow, we might plant them more! Maybe because their fast and reliable growth makes them an ideal crop for children to plant, adults tend not to bother with them so much.  But if you are sowing green salad crops in autumn and early winter, why not enjoy some crunchy fresh radishes with them?

Sow the seed very thinly in drills about one centimetre deep and fifteen centimetres apart. The soil should be tilled finely with no clods.  Keep the soil moist and as warm as you can in winter, watering them when needed with water that has been stored a few days in the greenhouse to avoid chilling the plants.  Cover them with bubble-wrap on frosty nights, but remember to take it off again in the mornings.

Warm moist conditions and radishes are attractive to slugs, so take precautions against them: one slug can wipe out a whole row of seedlings in one night.

Some radish varieties are better than others for winter sowing under cover. Check the seed packet before you sow, but try some anyway – radishes are very accommodating and the seed is not expensive.

Pesto and radish bruschettas

Soil Warming Cables – a Christmas Gift Idea

Christmas is coming and people are getting stressed by questions such as ‘what present can we get for (fill in the name yourself)?’ If they have a tunnel or glasshouse, how about something to increase their enjoyment of it?  They could use a soil warming cable in so many different ways that it is almost certain to expand the range of plants they can grow and/or extend their growing season.

The theory is simple. The cable is buried below the surface of sharp sand.  When warmed by electricity it warms the surrounding sand and any seedtrays or pots sitting on it.  Soil temperature affects plant growth more than air temperature.  Seeds germinate faster, cuttings root sooner and growth continues when the air temperature drops a bit too low for normal growth.

Insulating fleece or bubble-wrap over the plants will protect them from a few more degrees of frost due to the rising heat.  Adding a thermostat will save electricity when the sun warms the soil naturally; see https://greenhouseireland.ie/accessories/ .

You can heat a whole bed or just a small propagation area, but if the latter it’s more convenient to have it on a raised bench or staging in which case you should place insulation underneath it.

Electricity and water are an unsafe mixture. Make sure you use a qualified electrician to lay on power to a glasshouse or tunnel, and follow the installation instructions carefully.

Growing Herbs in a Greenhouse during winter

Growing fresh herbs all through the winter is one of the easiest and most satisfying ways to use a greenhouse. Clumps of chives, mint and marjoram and parsley plants can be potted up and brought inside to continue growing.  Basil, which needs lots of heat and is very tender, will stay growing longer in a tunnel or glasshouse than outdoors before the cold kills it.  Although bushy herbs such as rosemary and thyme are hardy outdoors all winter, potted plants under protection will produce mild, fresh-tasting young shoots long after outdoor plants have stopped growing.

Pot up herb plants or clumps in good soil or compost or a mixture of the two, water them well and leave them out of direct sun to recover for a few days. Then place them in good light in cool, airy and well-ventilated conditions.  Basil is best sown in small to medium sized pots and kept warmer than the others.  Water them regularly and don’t let them sit in saucers of water or dry out completely. Use water warmed by keeping it in the greenhouse for a few days to avoid chilling the plants.  Feed them occasionally and remove any dead bits.  If flower buds appear, pinch them out to keep them growing fresh leaves.  Watch out for aphids and guard against slugs: both stay active in the warmth of greenhouses much later than outdoors.  Be ready to cover plants with fleece, bubble-wrap, cloches or other protection on frosty nights.

Mizuna (horticulturalist Peter Whyte gives some tips for Greenhouse users)

Mizuna is one of the oriental greens that Europeans should grow and eat more. It’s best grown rather than bought because it needs to be eaten right after harvesting for maximum flavour and nutrient value, though it will keep for a couple of days in the fridge. Like lettuce, you can sow seed little and often all year round in a glasshouse or polytunnel. September sowings will produce deeply cut leaves up to April or May: single leaves can be cut off after about three weeks and whole heads after six to eight weeks.
Mizuna likes moist rich soil, so dig in plenty of compost or other organic matter before sowing. Sow the seed about a centimetre (half an inch) deep in drills about 30cm (12 inches) apart. Protect the seedlings from slugs. Keep it well watered and ventilate on sunny days – it is prone to bolting in hot dry conditions. If it does bolt remove the flowering stems right away to keep it leafy and sow another batch to replace it. Don’t worry if it wilts after a frosty night: it is hardy and usually recovers. It is a member of the cabbage / brassica / crucifer family so don’t sow it in the same ground as any of its relatives for at least three years to prevent disease build-up
Mizuna has a milder flavour than either mibuna or rocket, and is good in mixed salads. Like spinach it can be steamed, boiled or stir-fried but it shrinks a lot, so harvest plenty. ‘Kyoto’
is a good variety to try.