Coffee is obviously how many will start the day, but far fewer contemplate trying to grow some coffee beans for their morning brew.
If you are interested in growing coffee in the UK, the first thing you should know is that it is not possible to grow a truly exemplary coffee in our climate. The finest coffee grows in conditions very different to our own.
While a polytunnel can allow you to grow produce that would not otherwise do well in the climate of the UK, coffee does not thrive when grown in these conditions. That said, as a novelty, a polytunnel can allow you to grow a few coffee plants of your own and perhaps, with a lot of work, to brew up a cup or two of your own coffee.
The best coffees are grown at high altitude and in temperatures much higher than those found in the UK.
That said, growing a few coffee plants in containers in your polytunnel could provide a few handfuls of coffee beans.
The lush green plants can also be attractive house plants or ornamentals, which will bloom with small white flowers before producing the cherry-like fruits from which your cup of coffee is made. So even if you are not bothered about making coffee to drink, you may wish to grow this plant for its visual appeal in a heated undercover growing area or indoors.
It is far easier to grow coffee plants from your plants rather than from seed. You must be certain that your polytunnel will be frost free as coffee plants cannot survive even the lightest of frosts.
Pot your coffee plants into loam based compost in the early spring and aim to maintain a temperature of 24 degrees from March to September and 22 degrees Celsius for the rest of the year. But note that heating a space to this temperature throughout the year will likely be a costly process.
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Coffee plants can be purchased online from a number of retailers. It is best to select a variety suited to container cultivation (e.g. a dwarf cultivar) as this will make it easier to grow a coffee plant successfully in a temperate climate zone.
Most coffee is cultivated within the region commonly referred to as 'The Coffee Belt,' which spans between the Tropic of Cancer and the Tropic of Capricorn, running parallel to the Equator.
The term "coffee belt" originates from the shared climatic conditions across the region, characterized by warm daytime temperatures and cool nights, abundant rainfall throughout the year, high levels of humidity, and fertile soil. These environmental factors create optimal conditions for the cultivation of coffee beans, making the countries within this belt ideal locations for coffee farming.
To grow coffee successfully you need to provide:
Partial shade. (Bright but indirect light indoors.)
Temperatures of around 24 degrees C. year-round and temperatures that never fall below 15 degrees C. at any time.
Reasonably high humidity.
Rich, loam-based, moist but well-drained growing medium rich in organic matter that is acidic to neutral in pH.
The most important aspect when it comes to growing coffee involves selecting the right growing location – one where you are able to provide the conditions described above. Finding a location that will be suitable is certainly the biggest challenge for those who with to grow coffee in a temperate climate zone.
In the UK, to create the right conditions you will either have to grow the coffee plant indoors, or in a heated greenhouse or polytunnel. Outside, or in an unheated greenhouse or polytunnel, of course, temperatures will drop too low.
Even the inside of many homes will be too cool for at least some of the year to grow coffee successfully. The temperatures required are the main reason why growing coffee here can be such a challenging proposition.
A coffee plant should be potted up into a container large enough to accommodate the existing root system with a little space to spare around the edges. This container should be filled with a loam-based potting mix with added homemade compost, leaf mould or other organic matter.
Place the container with the coffee plant into a suitable growing location, watering well but avoiding waterlogging and keeping the plant out of any chilling draughts.
The best time to pot up a coffee plant is in the spring, once daylight hours have begun to increase and temperatures rise outside.
Coffee beans that you purchase to make your morning cup are of course roasted and so will not germinate. In theory, however, you could potentially grow a new coffee plant from seeds collected from a home-grown coffee plant.
The red berries that form on a coffee shrub contain seeds. These seeds may be dried and then roasted to use as coffee but you might also take those seeds, soak them overnight, then sow them onto the surface of moist potting mix.
Cover the seeds lightly and maintain temperatures between 27 and 29 degrees C. for germination to take place. Seeds should germinate within 6-8 weeks. Once large enough to handle, seedlings can then be potted on as needed and provided with the requisite growing conditions to continue to survive and grow.
Coffee grown as a container plant in the UK may need to be pruned annually to restrict its size. The best time to prune is in the spring, which you should cut back stems at a 45 degree angle just above a node, (the point where a leaf joins the stem).
Choose a dwarf variety, however, and you will not need to prune as much if at all, since these are slower growing and naturally remain more diminutive in size.
Coffee plants do not thrive when their roots are too restricted and it is important to avoid a coffee plant becoming root bound. You need, therefore, to repot your plant whenever the roots begin to emerge from the holes at the base of the pot.
Repot a coffee plant into a slightly larger container with new potting mix each time, making sure that each new container has adequate drainage holes at the base. Ideally, repot in the late winter or very early spring before new growth begins. Typically, you will need to repot every 2 to 3 years.
Caring for coffee in a temperate climate will of course take some work, since you will need to make sure the right growing conditions are maintained over time, and that the coffee plant gets what it requires.
Remember that a coffee plant will do best in bright but indirect light, or partial shade. In a full sun situation the leaves can scorch and the plants will suffer.
Again, choosing the right growing medium is crucial. Make sure that it is a loam-based mix, that is moist yet free draining and acidic to neutral in pH. Add an organic mulch to help retain soil moisture and boost fertility.
Water regularly and do so with rainwater wherever possible. Aim to keep the growing medium moist but make sure that you do not overwater and make sure excess water can drain away freely.
Remember that when growing a coffee plant you will need to keep temperatures throughout the year at around 22-24 degrees C. for best results, and should never let temperatures drop below 15 degrees C. in the location where your coffee plant is growing.
Coffee plants should be fed with a balanced, organic fertiliser every month or two over the spring and summer.
There are two main types of coffee plant – Coffea arabica and Coffea canephora var. robusta, also known simply as Coffea robusta. The former tends to be milder and more fruity, and also more acidic, than the latter.
A dwarf variety of Coffea arabica, called 'Nana' could be a good choice for those cultivating coffee in a container in temperate climes.
Growing your own coffee has both advantages and disadvantages that you should weigh up before deciding whether or not this is something that you are interested in doing.
You can learn about coffee cultivation and broaden your horticultural skills.
By growing some coffee you can reduce your carbon footprint a little since coffee will not have to travel miles to reach you. (As long as you heat your growing space sustainably.)
Your own coffee will be ethical and can be organically grown, meaning that you get a cup of coffee you can rest assured has not done any harm.
It it unrealistic to expect that you can ever grow enough coffee for more than a cup or two at most as a home grower. So don't expect to make a year's supply unless you have a lot more undercover growing space.
Coffee plants need specific growing conditions that it can take quite a lot of effort, and money, to maintain. So your cup of homegrown coffee is a novelty that might not really make up for the money expended.
After growing coffee, you still need to go through an extensive process of fermentation, drying and roasting before you can turn it into a drink.
One other reason that coffee can be challenging to grow in a temperature climate is that the plants can fall prey to a number of pests and diseases, and encounter a number of other common problems.
Like other plants grown undercover, coffee plants can be affected by red spider mites. These thrive in warm conditions so keep a close eye out for these pests and wipe them away where possible. There are also biological controls available to deal with severe infestations.
Coffee plants are high risk for carrying a bacterium called Xyella. This can cause dieback, leaf scorch and ultimately kill the plant.
Source your plant from a reputable nursery and check that your plant is UK grown. Plants that have been raised in the UK are fortunately at low risk for this disease.
If you see brown spots on the leaves of a coffee plant, this may be a fungal leaf spot. Improving airflow around plants and ensuring good ventilation can help to prevent this problem from arising or spreading. Remove affected material promptly to prevent its spread.
Brown leaves can also be an indication that leaves were scorched by the sun, or that waterlogging and root rot have occurred. So rule out environmental problems before looking for other issues when leaves turn brown.
Remember that polytunnel growing for coffee plant would only be possible where the space is heated throughout the year. Extra protection for a coffee bush may still be needed and while you need to ensure adequate ventilation you also need to keep the coffee plant free from draughts.
BBC Good Foods. (2020) Coffee Recipes. [online] Available at: https://www.bbcgoodfood.com/recipes/collection/coffee-recipes [accessed 21/03/24]
