Polytunnels | Polydome

May – Raindrops Keep Falling on my Head!

Our frequent rainfall keeps Ireland green and beautiful. However, since you’ve put up a tunnel and blocked it out, now it is up to you to keep your plants hydrated!

Water, along with oxygen, sunlight and soil, is a basic need of all plants, even though their requirements can vary considerably. From one type of plant to another, from tiny seedling to full-grown, from pots to open soil, and from overcast days to sunny ones this job can keep you on your toes!

How Often?

There is no correct answer to this, but you want to keep your plants somewhere between waterlogged and parched! If the soil feels dry below the top inch or two, it is probably time to water. If plants start to droop or lower leaves begin to yellow they are too dry. When you see moulds and mildews appearing on the soil surface, it is likely too damp. Intuition for this develops quickly enough.

Morning vs. Evening

This is a point of debate. Most everyone agrees that in the heat of the day is not the best time to water. However, if a plant is wilting or is a tiny seedling drying out, it is always better to water than let the plant suffer damage or death. The advantage of evening watering, particularly in very warm weather, is that the moisture can be retained overnight and will evaporate the next day once the heat soars again. The advantage of morning watering is that if you have a hearty nocturnal slug and snail population you can discourage them from slithering along on moist soil munching all of your plants overnight by keeping things at their driest then.

Manual vs. Automatic

This is another point of debate and probably something in between is ideal. Automated systems can be put on a timer and adjusted throughout the season. This is ideal to cut down on time and effort, but it is always wise to monitor the situation and not fully depend on automation. Manually watering allows you to reach every plant and give more or less in specific situations, but it does require a dedication of more of your time. Polydome does supply irrigation equipment, including simple battery-powered automatic timers.

Overhead vs. Underneath

Overhead watering, including overhead irrigation lines and the use of a hose, does have the advantage of washing down leaves like the rain. However, some plants work better with underneath watering, from watering a tray under a pot to using capillary mats or low-level drip lines. Reason for this vary, but this often suits plants that are prone to mildews or blight from remaining damp or leaves that scorch from being watered in the sunlight. In a protected structure where there can be less natural wind and ventilation, this is often an ideal solution. An example of this is using low-level drip lines for tomato plants to avoid blight or feeding potted cyclamen from a capillary mat to keep their leaves healthy.

In the winter, having a roof that keeps excess rain out is a great advantage to many plants. However, the surrounding areas outside the tunnel moisten the areas near the edge, so this is something to bear in mind.

So, the next time it rains, enjoy the raindrops! They are little droplets supporting life!

March- Propagation time!

It’s March and high time to start some seeds! Here are a few tips for success.

1)Unless you are sowing directly into the soil, having a bench that is the correct height is a must. This saves your back and also allows you better precision when sowing tiny seeds that are difficult to see.

2) Next, follow the instructions on the packet. Not all seeds are sown in the same way.

3) There are several factors involved in triggering a seed to germinate. These include light, temperature and moisture. At this time of year, the temperature is too low for certain seeds, so using a heating mat or heating cables in sand can speed up germination, resulting in a stronger plant.

4) It is a good idea to label everything clearly as you go along. This can avoid confusion later on when the little darlings start to emerge and you don’t know who is who! It is also a good idea to record when and what you sow in a notebook or diary for future reference.

5) A seed is a tiny miracle that contains everything it needs for life. However, once the outer coat has been broken down, the emerging seedling is very vulnerable until it has formed sufficient root to acquire moisture and nutrition for itself. At this stage it is vital that it isn’t allowed to dry out. Here are some ways to ease your seedlings through this delicate stage:

*Pre-water the growing medium well.

*Partially cover seed trays with polythene or glass (allowing some air flow) to retain moisture.

*Gentler forms of watering such as using a watering can with a rose, overhead irrigation, drip lines or capillary matting are preferable to using a garden hose on young plants. (Of course, the more vigorous plants like peas and beans will withstand much more than a delicate cactus seedling.)

6) Did you know that keeping your young plants up on shelving isn’t just for convenience? It also serves to protect them from pesky mollusks. Yes, slugs and snails. They love damp, dark corners to hide in during the day, saving their energy to come out and graze all night. So, keep your root babies as far away from them as you can!

Best of luck to everyone who is setting out to sow seeds for the first time or the 50^th time!

February- Is it Spring yet?

As the days start to get longer, a new season is here and signs of life are starting to appear all around us. The sight of snowdrops and daffodils remind us that the years march on regardless of what else is happening in the world around us.

On beautiful days when the sun gives that early spring glow we can feel that the year has turned and are tempted to sow something. The reality is, though, that we can still have plenty of wintery weather ahead of us at this stage and it is too early to start anything without protection.

This is the time of year where a polytunnel really shines. As the sun comes out, there is a bit more heat and gentle growth in your greenhouse. With a heated seed bed, you can begin to start your tomatoes, peppers, lobelia, lettuce, onion or pea plants. If you are into bedding plants, you can start lobelia, salvia or sweet pea. Electric heaters or frost protection fleece will help protect your young seedlings from the elements even further.

It is also at this time of year that having a well-built polytunnel really pays off. There is nothing as discouraging as seeing all your young plants destroyed due to a damaged structure after a windy night.

Polydome polytunnels are built to last and withstand the unpredictable Irish weather to give you peace of mind.

So enjoy the season and being one step ahead of the elements!

This photo of a beautifully laid out tunnel interior was sent to us by Rosie Green from Dingle. Thank you, Rosie!

Onions from seed

Most people plant onions as sets; semi-mature bulbs which will hopefully grow bigger and be harvested before they go to seed. But you can also raise onions from seed sown in your greenhouse instead of from sets planted later. This is especially useful on cold, wet soils or in cold, wet springs, as onions cannot tolerate those conditions. Seed-raised plants are cheaper than sets, you have more varieties to choose from, and the plants are less likely to bolt or be pulled out of the ground by birds. On the downside, seedling onions need a longer growing season so February is definitely the last month for sowing, and the longer growing season means more time for pests and diseases to attack them.

Sow the black, angular seeds thinly in a seed-tray, or in modules at up to five seeds each. Keep them at about 10-15°C. The seedlings come up in loops, and you should prick them out from seed-trays into pots before they pull their tips out of the compost and straighten up. If multiple seedlings come up in modules, either leave them to push each other apart later as they grow, or single them with a fine-pointed scissors to give the one remaining plant room to grow a bigger onion. Keep the compost neither bone-dry nor saturated. Grow on the plants in bright, cool conditions until they have two or three leaves, harden them off well and plant them out at about 15cm apart each way. Wider spacing gives you bigger bulbs, and tighter spacing gives smaller ones.

You can also plant sets in pots and give them a head-start under cover, planting them out only when conditions improve.

Growing Basil

Basil is easy to buy from the shops, but you can grow a wider range of types yourself at lower cost to you and the environment. The type sold in non-returnable pots is usually sweet basil suitable for salads and pesto, but there are also cinnamon and lemon basil, varieties with purple leaves that look great in green salads and spicy or liquorice-flavoured Thai varieties that combine well with Asian food.

Basil is a fast-growing, tender annual that needs lots of light, heat and water. Being very sensitive to cold, it is an ideal candidate for tunnels and glasshouses, especially in our unpredictable summers. It improves the flavour of tomatoes when served with them, and some say that it also does so when grown with them. It grows best in well-drained acid or neutral soil. Sow a succession of crops, but just a couple of plants each time is enough for regular use unless you want extra for pesto. Either sow them in cell-trays or in situ in the greenhouse soil, thinning them to single plants as soon as they are big enough to see. Use a scissors to avoid root disturbance. Thin or place the plants to about 30 centimetres apart. Harvest leaves as soon as the plants are about 20 cm tall, by cutting off shoot tips. Leave on the lower leaves until you discard the plant; they will produce the food to grow new shoots from the lower side-buds. Even if you need no basil, cut off the tips to prevent flowering (which makes the leaves bitter) and encourage fresh sprouts to grow. Surplus leaves can be either frozen for later use or composted, and the flower-buds are edible too.

Sweet Corn (a post intended for April, sorry for the delay)

You can grow sweet corn outdoors in a good summer, but for a more reliable crop you need a greenhouse. April sowings are best done in pots but in May and June seed can be sown directly into its final position. Sow one fresh seed about 1cm deep per tall pot of free-draining compost: if using older seed sow multiple seeds per pot and single the seedlings later with a scissors. Keep the compost warm and not too wet. Sweet corn roots go very deep and do not tolerate confinement, so plant out your crop as soon as possible. Choose the tallest space available, although it won’t matter if the tops are bent over at the roof. Dig large planting holes 30cm apart in a square block to aid pollination. Fill them twice with water and add in some compost when planting; corn needs plenty of water and feeding.

If space is short, you can plant corn between rows of greens due for harvesting soon. Keep watering and feeding. When the sticky tassels appear on the lower female flowers, shake or tap the plants gently each day to shower pollen down from the male flowers above and ensure well-filled cobs. Cross-pollination gives poorly set and less tasty cobs, so if growing different varieties try to plant them as far apart as possible. The cobs mature close together, so sow later crops to extend the season. The cobs are ripe when the tassels darken and wither, and punctured kernels leak milky fluid. They dry up and get starchy very soon, so harvest them promptly, cook then immediately for four minutes in boiling water, and enjoy.

New Roll Up Side Ventilation System

At the recent Bloom Show we premiered our new roll up side ventilation system which can be fitted to our full range of Garden and Professional Polytunnels. This simple system provides an economical solution for roll up sides and can be fitted to one or both sides of the Polytunnel. A rainwater collection gutter is available as an optional extra feature. We will have this fitted to one of our Polytunnels in our display area this summer.

Polytunnel rainwater collection gutters — New aluminium rainwater collection gutter

Polytunnel roll up side ventilation — New Polydome Roll up side ventilation system

End of the line – by our blogging Horticulturalist Peter Whyte

October is the month when production of greenhouse tomatoes, aubergines and peppers usually comes to an end. With falling temperatures and longer nights, growth is slowing down and your plants will be less able to ripen fruit. Remove all flowers as they are unlikely to set usable fruit in time for them to ripen this late. Thin out some of the fruits already set, especially the smaller ones. Stop shoots from growing any more by cutting off their tips. The above actions divert all the plants’ resources into filling the remaining fruit, so you get bigger, riper, tastier fruit instead of many small unripe ones. Do this earlier or later depending on your location and how mild the autumn is.

With the rising humidity, disease control becomes more important by the day. So make sure to remove any dead leaves, spent plants, weeds, rubbish and dropped fruits from the greenhouse. Open the vents or doors on sunny mornings, but close them up earlier in the evening before it gets too cold. Feeding should have ended in September, and watering should be reduced to match the plants’ lower needs. As a rule of thumb, don’t water until the soil surface is dry. Avoid wetting the leaves.

By about mid-October it can be too cold to ripen tomatoes well. If so pick all the fruit and ripen them indoors in a dark, airy cupboard. Don’t leave them on a sunny windowsill: if they once get heated above 35°C (95°F) the red pigment is destroyed and they stay pale and blotchy. Some people put a ripe apple or banana with them to speed up ripening with the ethylene gas it gives off. Remove plants when their fruits are all picked, and clean up the greenhouse for the winter.

Multifunctional Canopy Structure

We recently built a canopy structure for Hannah’s Garden in Birr (formerly Ward’s Garden Centre), it is the kind of structure that customers ask us about for numerous applications. This type of structure can be used in Industry to keep pallets out of the rain, for livestock, for Garden Centres to avoid plants getting too wet (and of course customers too), it can be used for drying timber, hanging up your washing line, a car port (we have had people ask for this including for Vintage cars) – etc. etc. (I feel a competition coming on here for readers to think up practical suggestions of what it could be used for). This structure is the same design as our standard 6m wide Model but with extra height and a heavier frame than normal to carry the extra height. Thanks to our well equipped workshop and stock of steel we are able to customise our Polytunnels where the need arises.

Why not visit Hannah’s Garden when you come to Birr? It is on the Tullamore Road opposite Lidl.

Potatoes for May

If you like your early potatoes early and you have enough room, why not plant some in your greenhouse in January? They could be ready for harvesting as soon as May. Yields can be modest, but the flavour of fresh early potatoes is unbeatable. Choose seed potatoes of an early variety, and stand them on a warm bright windowsill indoors to start sprouting. Keep the eyes facing upwards so the emerging shoots will be straight and tall.

When the sprouts are about five centimetres tall plant the seed potatoes in the greenhouse, either in the ground or in large pots. Some compost or well-rotted manure could be added to the soil, but not too much if slugs are a problem. When planting take care to trickle soil gently down between the sprouts to avoid damaging them. Some growers who use pots plant the seed potatoes in half-filled pots and add more soil as the sprouts grow up, always leaving their tips exposed to the light to speed up growth.

Keep the soil moist but not wet, ventilate the greenhouse (or bring pots outside) on warm days, and protect the plants from frost and slugs. Add soil around the bottoms of the stems to stop light from greening potatoes near the surface. You can start eating the potatoes when flowering is over, but the potatoes will continue growing bigger until the foliage dies down. They taste best when freshly dug, so unless you need the space or have a slug problem dig them only as you need them. Bon appétit!