Sunday, 15 February 2015

Growing Hops in Ireland - FAQ


Peter's Oast House in Kent, one of
the few traditional Oast Houses in
England still in use

Long story short, a few years ago I was interested in growing hops commercially in Wexford with my buddy Fergus. As part of our research I visited the some lovely people in Kent who are involved in the industry and have been for quite some time, including Peter Hall, a fascinating gentleman who has been growing hops on the family farm for decades. Peter has the largest "tall hop" organic hop farm in the UK with over two thousand Target plants in a hop garden of around one hectare. The information I gathered while I was there I have gathered and compiled into this FAQ. I hope you find it useful!

I want to grow hops. Where can I buy them?
I have used Eickelmann in Germany and Essentially Hops in Kent. I have visited Essentially Hops at Chalkpit Farm and met with the owners Amanda and Mike Barker and I highly recommend them.

Corridor in Peter's hop garden.
Target is the only variety grown.
What are rhizomes?
Technically bulges or lumps in the roots that are food stores, but people use the term to refer to a section of root that has a rhizome or two, i.e. a root cutting.

Is it necessary to buy/acquire rhizomes?
No. Transplanting root cuttings during the growing season will work just fine.

What's a root cutting?
The easiest way to propagate a plant is to do a root cutting: Find a shoot that is 25-50mm above soil and gently dig back the soil around it. When you have around the same length of root exposed, snip it and transplant it to a medium sized pot of good quality compost. Place the pot somewhere where it will get lots of sunlight and easy conditions, like a kitchen window or a greenhouse. Do not let it dry out. When it has outgrown the pot then it's time to move it outdoors to a more permanent location.

What varieties will grow well for me?
If growing outdoors: English varieties do well, German do surprisingly well, American don't do so well. New Zealand varieties are nearly all proprietary. All will grow, but with varying amounts of success. The further north you are the shorter your day, which in theory will affect growth, but for an amateur grower in Ireland this is unlikely to matter. Alternatively anything will grow well in a poly tunnel!

Hold on, what are "proprietary" hops?
Varieties which are genetically "copyrighted", and cannot be grown without a licence from their owner. Hops marked with a ® or ™ means a licence is required (and in many cases not available) and as a general rule the New Zealand varieties are proprietary. Most of the US proprietary varieties originate from a small number of farms/breeders but unfortunately the own the majority of the "hipster" hops. Fortunately the venerable Cascade is not proprietary, as it was developed by the USDA, a public body. Most recent English hops were developed at Wye College, also a (formerly) publicly funded institution, so most are also free, e.g. Wye Target, although Charles Faram is breeding new proprietary hops in England.

What sort of conditions do I need to grow hops?
Hops need shelter from the wind. This is critical. They do need air circulation though, to help prevent mildews. After that they need plenty of sunlight and unless you can grow them in a southerly or south westerly aspect they may not get enough sunlight, in which case they won't produce any cones.

How big will plants grow?
Hops have a tendency to wind themselves around something and full height plants ("tall hops") will typically grow to 20 feet/6 metres. There are however some dwarf varieties which will only grow to between 8 and 12 feet/2.5 to 4 metres.

Do I need to erect wirework or some sort of trellis for my plants to climb?
That depends. Bines will need something to climb: They will climb up other vegetation, like trees, and on fences etc but you may need to provide them with something more suitable to climb on if they're not doing very well.

I'm going to put up some ropes or wires for them to climb. What should I used?
Traditional growers in England use coir rope, a rough rope made from coconut hair, but that's not readily available here. What works fine is any sort of rough rope like clothes-line rope (nylon) which can be had in any Tesco or Woodies etc. Coir rope has the advantage of being bio-degradable, so when cutting down bines the coir rope can be cut down too.

How many ropes should I provide?
Commercial growers provide each hop hill (i.e. plant) with typically four ropes and will train three to four of climbers up each rope. Your mileage may vary, especially in year one and two.

Will they grow in pots?
Yes, but not well, and will be pot bound (i.e. the smaller the pot the smaller the plant). This limits their chances of producing cones. If potting use John Innes No.3 compost, available from good garden centres (The Orchard in Celbridge has it).

What sort of soil do they need?
Deep, rich soil, on a dry bottom. Brick earth over chalk is ideal. Good soil moisture and fertility are essential in order to sustain growth of the hop plant each year. The ground should be generally well pulverised and manured to considerable depth by plough or spade before planting.

When do they need to be planted?
Like any other perennial plant, they're dormant in the winter, and come to life around March.

What kind of fertilizers do I need?
They should be planted in manured soil, and in February treated with a fertilizer rich in phosphorous and potassium before the plant begins the growing year. During the growing season they need to be fertilized with nitrogen. (I cannot recommend any particular fertilizers, but I see mention of tomato plant food which can be had in any garden centre or Tesco, Woodies, etc)

My plant has started growing and the first shoot is growing very fast!
Pinch it out, i.e. cut it off. The first grower has very long internodal gaps (i.e. the length of stem between nodes, where the hops will appear), and for its size it will give less cones than slower growing ones. Commercial growers pinch out the first grower and then will cultivate 12 to 16 growers from each hop hill (i.e. plant), training them as required. Additional growers are also pinched out, as they only use up resources.

The tip of a grower has been broken off, what now?
One of the laterals (i.e. sideways growing shoots) at the node below the break will take over, and will start to grow up. i.e. don't worry, it'll sort itself out.

What pests am I likely to have to deal with, and how do I deal with them?
Very small green spiders called aphids. These are very common, and usually hide on the bottoms of the leaves. Less common is greenfly. Fortunately the treatments are simple. You can spray the whole plant with soapy water when it's raining (when it's not raining it can be difficult to cover the whole plant). This drowns the buggers. You can also use a domestic pesticide. Or the most environmentally friendly way is to make sure your garden has a good stock of ladybirds, as they eat all the various pests.
Powdery mildew
(photo from Wikipedia)

What diseases am I likely to come across?
Damp conditions and poor ventilation will lead to mildew. There are two types, downy and powdery. Both are white, powdery looking, look like they will rub off, but won't rub off. Downy mildew occurs on the bottom of leaves, powdery occurs on the tops of leaves. The conditions that encourage mildews on hops will also encourage them on other plants.

There is white stuff on my leaves, help!
It's mildew. See the above.

There are little green things that look like tiny spiders all over the bottoms of my leaves, help!
Aphids. See the bit on pests, above.

My leaves are poorly and turning brown/black at the edges, help!
Not limited to, but probably wind burn. The location is not sheltered enough from the wind.

What is verticillium wilt?
Also known as vert and wilt, and officially known as Verticillium dahliae. As we have no native hops industry in Ireland this does not exist in hops in Ireland. That's not to say it doesn't exist in Ireland as it does on many plants including strawberries. The isolate which affects hops though is not common here (and is not the same as with strawberries) so you're very unlikely to be affected by it. It is a fungus in the soil, and it destroyed large swathes of the English hop industry. It still exists in pockets in England, but is treated very seriously, like TB in cattle is treated here.

How will I know when it's time to harvest?
Hops are generally ripe for picking around late August to mid September. Different varieties are early, mid, or late-season croppers, so all your plants may not be ready for harvest at the same time. You will generally know as the cones will still be green, will have stopped growing, and the texture will have started to turn papery.

How should I pick my hops?
You can pick them by hand off the bine, or you can cut down the bines completely and bring them into a shed or garage and pick them there. The latter is really a necessity with tall hops.

How much can I expect to get per plant?
A plant will take three years to establish before it produces a full crop, and then with good growing conditions you could expect between 2 and 3kg of wet hops per plant.

What are wet hops?
Wet or green hops are fresh off the bine and have a very high moisture content.

Can I use wet hops to make a brew?
You can, but if your recipe calls for a certain amount of dried hops you will need approximately five to six times as much wet hops.

Should I dry my hops?
If you plan on storing them for a while then you must try them.

How can I dry them?
It's easy to get carried away with elaborate systems for drying hops, but left in a paper bag
in the hot-press ("airing cupboard") for 24-48 hours will usually suffice, and is cheap and simple.

How will I know how much Alpha Acids are in my homegrown hops?
You will need toluene and a UV-vis spectrophotometer. If you don't have those you won't know for sure but expect it to be within the typical range of the variety. If there was good sunshine and general growing conditions that alpha acids are likely to be a bit towards the higher end, and conversely the opposite applies if conditions were poor. Also, if you're going a US variety our really good summers are their average to poor summers so you'll need to take that into account.

What should I do with my plants for the winter?
If in the ground they will usually survive the winter without any problems. However if there are signs that we are going to have winters like those of 2009 and 2010 then it would be advisable to cover the hills with plastic. If you are growing in pots then move the pots inside to protect from hard frost.

What is vernalistion?
Vernalisation (from Latin: vernus, of the spring) is the acquisition of a plant's ability to flower or germinate in the spring by exposure to the prolonged cold of winter. After vernalisation, plants have acquired the ability to flower, but they may require additional seasonal cues or weeks of growth before they will actually flower. Ironically this means if we have a very mild winter then there is the risk that plants will not flower the following year. Some hop plants are more sensitive than others and it is the considered opinion that Boadicea (bred to be aphid resistant) for example will not grow in Ireland as the winter is too mild.

Are there any wild hops in Ireland?
Yes. There was a hop growing programme in Ireland which started in the 1960s and was centred around Bennetsbridge in Co. Kilkenny. However a century or two earlier some large estates would have had their own beer brewed and some would have grown hops (not all as a lot of beer in Ireland didn't contain any hops). Indeed Arthur Guinness's father, Richard, was employed by the Archbishop of Cashel, Arthur Price, and used to brew beer for his estate in a brewery close to where the RC church in Celbridge now stands. Price is buried in St. Mary's CofI church on Main St., Leixlip, down the street from where Arthur's first brewery (in his own name) stood.

(I plan to do a more complete history of hops in Ireland a bit later)

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