Tomatoes and potatoes are so closely related (compare their flowers) that they are both susceptible to Late Blight. Of all the fungus diseases that attack tomatoes, blight is the most severe. In warm, damp weather in July the tiny fungus spores drift in through open doors and vents, and germinate quickly where they land on damp plants. The fungus spreads out to make large dark spots on the plants that join together and blacken whole leaves or stems. Brown sunken patches appear on the fruits and they rot. Mould then appears on the surface, releasing more spores to spread infection. There are no approved sprays for blight control on tomatoes, so use cultural controls instead.
The spores are spread by wind, hands and water-splash. Close doors and vents on cool days to keep the spores out. On warm days open glasshouse vents and tunnel doors to air out the greenhouse. Keep leaves dry by watering onto the roots; avoid overhead watering. Water in the mornings so the plants are dry by nightfall. Remove the lower leaves by breaking them upwards (not cutting, as the wound heals slower) and break out side-shoots to improve air circulation around and through the plants. Remove all potato crops from the greenhouse by mid-June to stop them infecting the tomatoes. Remove and destroy infected leaves and fruits immediately, before they infect their neighbours, but wash your hands before handling healthy plants. Don’t compost infected material as some spores can survive composting. Grow tomato varieties selected for blight resistance such as ‘Ferline’ and ‘Legend’: they are not fully immune but it helps.
Looking forward to the Bloom show which starts next week – on the 1st of June through to the bank holiday Monday (the 5th). We will have two stands this year, one for Polydome and one for Greenhouse Ireland – adjacent to each other – stand numbers OR39 and OR40. By then our new website, Greenhouse Ireland, will be launched for showcasing Janssens and Griffin Glasshouses. We will be showing some new gable ends on the Polydome stand – our new Aluminium Sliding Door for our Garden Polytunnels and a new steel gable with a net vent that you can open and close like a window. On our Greenhouse Ireland stand we will have an exciting new model called the Modern from Janssens – in a mad red colour! We always enjoy exhibiting at Bloom, so looking forward to seeing many of our existing customers as well as meeting new faces.
By early summer the plants that were thriving may grow slower and look a bit pale. A common cause is hunger: the roots of a plant may have filled the available compost or soil and exhausted its mineral reserves. Plants in pots, containers and grow-bags are most at risk because their roots have nowhere else to go: at least plants growing in greenhouse beds or borders can spread their roots out a bit further. Hungry plants grow slowly with pale leaves; their lower leaves may drop off and flowers may be small and poorly coloured. Overfed plants are soft, lanky and leafy and the leaves may have brown spots and wilted edges.
Never feed dry plants. Water them first or the salts in the feed may scorch their leaves and roots. Granular and other solid fertilisers are fine for crops in greenhouse soil but liquid feed is better for plants in containers and grow-bags. Feed them only when they are growing. Never make up liquid feed stronger than advised in the instructions; the manufacturers already recommend the maximum safe level because they want to sell you more feed. This is even more important if foliar feeding by watering it onto the leaves. If you want vigorous leafy growth as in salads use a feed higher in nitrogen (N) than potash (K) but if you want flowers and fruit use a high-potash one such as tomato feed. You can make your own liquid feed from soaked comfrey or nettle leaves, but one of the best organic feeds is made from Irish seaweed.
May is a dangerous month for greenhouse users. With all the talk about global warming and the evidence of it everywhere, you can easily forget that the risk of frost continues into May. The last likely frost might be in early May near the coast, but inland you are not in the clear until end of the month. Global warming is a long-term trend but there are still short-term highs and lows on the temperature graph.
Plants grow fast in May and quickly need more space. It’s tempting to move some plants out of tunnels or glasshouses to make room for the rest, but harden them off properly first and keep a sharp eye on the weather forecast. Be prepared to carry them back in on evenings when frost is predicted. And if you were tempted by the early displays of tender bedding plants in a garden centre, remember to bring them in too. Cold frames can protect plants from several degrees of frost, and plastic cloche tunnels give some protection from lighter frosts. Single small plants can be covered with upturned buckets or light materials such as straw or bracken fronds. Just make sure the wind doesn’t uncover them overnight and that you uncover them yourself next morning.
frost on leaves
Poor Man’s Orchid or Butterfly Flower is a half-hardy annual which, when well grown, is covered in flowers that look a bit like orchids or butterflies. It is much easier to grow than true orchids. The flowers can be a single colour such as white, lavender, pink and red, or be bi-coloured, and/or have yellow throats. They last well when cut. Like all half-hardy annuals they can be grown from seed in a greenhouse and planted outdoors after the last frosts are over. But they can also be kept in a well-ventilated greenhouse to flower all summer. They do very well in pots and containers, where the root restriction seems to encourage them to flower better.
Sow the seed in trays or small pots; varieties differ in their need for light for germination so follow the seed-packet instructions as to whether to cover them with compost or not. Keep them at about 60°F / 15°C for 2-4 weeks; they are slow to germinate. Prick out the seedlings when big enough to handle, and pinch out the growing tips as they get taller to keep them bushy. Keep them in full light but shade them from hot sun. They prefer fairly cool conditions and become drawn and spindly if too warm. They don’t tolerate wet so give them perfect drainage, water them only when the compost is dry on top and never leave containers standing in saucers of water. Give them some tomato feed every two weeks. If you have a heated greenhouse you can sow Schizanthus in August or September for overwintering. Watch out for greenfly; the ferny foliage hides them well.
Thanks to Cambridge University for the photo.
A new Greenhouse has just been added to our display area, a Janssens Senior Victorian with 10mm twin wall polycarbonate.
Twin wall polycarbonate is particularly popular on the continent. One of the advantages is that it is virtually unbreakable, it provides insulation and diffuses the light to reduce sun scorch. One cannot see clearly through it though. It provides excellent insulation so if running a heater your fuel costs will be much lower than a Glass Greenhouse without insulation.
10mm twin wall polycarbonate is much stronger than the light 4mm and 6mm sold with cheap Greenhouses.
The size also is a new one to our display area being 2.36m x 4.58m.
Being a Janssen Greenhouse this model has the benefit of an extremely strong ‘box section’ aluminium frame which is powder coated in either Green or Black. This model with 2.01m high sides, a single sliding door, three roof vents and a louvre vent is €4,405 including delivery for the self assembly kit.
There are lots of optional add ons.
March is about as late as you can sow aubergine seeds and expect a reasonable crop. You could sow as early as late January if the weather is mild enough or if you have frost protection heating in your greenhouse. Cell-trays allow you to plant the young plants with less root disturbance, so they grow away faster than plants pricked off from traditional seed-trays. Sow two seeds per cell (if both come up snip out the weaker one). Place them in a heated propagator or on a warm windowsill; the ideal temperature is 20-25°C (68-77°F). Keep the compost moist but not wet. The seedlings can take up to three weeks to emerge.
Set out the plants in your greenhouse as soon as their roots fill the cells or the first flowers appear, if by then you can keep them above 10°C (50°F) or so at night. Night-time fleece covers help. Alternatively pot them on into slightly bigger pots that can be brought into the house at night. Space the plants about 45cm/18 inches apart for normal, and 30cm/18 inches apart for dwarf varieties. Pinch out the growing point s of the main stems when about 25cm/10 inches tall to encourage the plant to bush out. Keep conditions warm, bright and humid.
Pollinate early flowers with a small paintbrush; later flowers should need less help. Start liquid feeding with tomato food when the first fruits form, and mist the plants with water to discourage red spider mite. Leave no more than five fruits per plant and remove further flowers to divert their energy into filling the existing fruit. Remove dead bits from the plants to discourage grey mould fungus, and watch out for slugs, whitefly and greenfly. Good varieties to try are ‘Black Prince’, ‘Dusky’, ‘Bonica’ and ‘Giotto’.
Delighted to say our new phone system has been installed. We just need to get used to the new buttons and bells and whistles and tweek things a bit. Customers should also hear professionally recorded on hold messaging. Thank you for having borne with us.
Our new phone system is due to be installed on Tuesday which will be a terrific relief.
In the meantime please bear with us. We have only one incoming phone line working and have had to divert that to a mobile.
You can of course email us at firstname.lastname@example.org
We will be open for visitors as usual on weekdays and on Saturday from 9am to 5.30pm (closed for lunch between one and two).
You can get directions to us on the How to find us section of the home page of our website.
Many thanks, Jonathan Pyle
In case anyone is having any difficulty getting through to us, I apologise. Our Eircom phone system has gone kaput and they say that replacement parts are not available now that it is 7 years old (after charging 180 euro for one hour to advise me of that). I like the idea that whenever something goes wrong to use the opportunity to improve the situation even better than it was before the event – so we will be installing a new more efficient system as soon as the new providers who are based in Birr as it happens can do so. Have to pat the new people (Intellicom) on the back, I called and enquired about a new phone system, within one hour a sales man was in our office, two hours later he was back with a technician to do a survey and before the end of the day a quotation received and price agreed. Way to go lads.
In the meantime while we are sorting out this issue please contact us on (086) 805 8550 or email us at email@example.com