This chapter is for the dedicated potato lover, who wants a plentiful supply of potatoes for every week of the year and is prepared to put in a bit of effort to achieve it. if you just want to do what everyone else does, then stick to then traditional: first earliest, second earliest and main-crop plantings varieties and dates, I recommend Garden Focused for the traditional way of growing.
Potatoes store really well and so with only a little effort it's possible to have a crop all year round. What's more challenging is to have the full range of potatoes: salad, baking, roasting etc every week of the year. In fact baking potatoes are a particular challenge and one that we only solved in 2021. Since potatoes are one of the commercial crops that's most heavily and frequently spayed with with fungicide it's a high priority for us to grow all of our own and all year round.
Early Charlotte baking potatoes in July
This chapter focuses on early and late potatoes, main-crop potatoes are very well documented elsewhere and so I've only briefly described the way I grow them for completeness. Check the links at the end of the chapter for other excellent resources on well established techniques.
As always what works for me, might not work for you, so experiment and find your own way.
There are six main techniques in our armoury for growing year round potatoes and you can pick and choose between them, depending on how much space you have and the type of space. Fundamentally though you need to be able to start your potatoes off early and protect them from the elements.
Potatoes are hungry plants and there are dedicated organic and in-organic fertilisers tuned specially to their needs. These are fine, but many people - including me - have good success with Blood Fish and Bone, others swear by poultry pellets. I generally go for half a handful of BFB per tuber, 2/3 in the root zone and 1/3 in the 6" above the root zone. Blood Fish and Bone is a slow release fertiliser so that's all that should be needed through the plants life. I like to keep life simple, but some people recommend a more complex feeding regime, the best resource I know of is Garden Focused, if you want to review that.
Many people are successful saving last years potatoes and using them as next years seeds, but there's always a possibility of building up disease when you do that. I do both, I save my last bucket of Swift and Charlotte potatoes for seed, but I buy the rest.
The main reason that I save is that I start my super earlies before the seed companies make potatoes available. I like to have mine ready to plant in January, for a harvest in early April.
Regardless of how you source your seed potatoes though, you need to consider how to store them and there are a few options:
Lets look at these in more detail
In a cold place in compost (normally the compost they grew in)
This is perhaps the easiest way, grow you seed potatoes in a tub, then put the tub somewhere frost free, but cold, protect from slugs and rain and leave them to it. Make sure the compost stays moist, which it will if it's cold. The tubers keep in great condition and don't start sprouting until early April.
However it takes up a lot of space and you don't know what you will find when you empty out the bucket, you might find rotting tubers, or small tubers etc. I don't do this for seeds, it's too risky, but I do it for my winter/spring potatoes for eating.
In a cold dark place, above freezing
This is a great way to store potatoes. Keep them in a thick paper sack, in a cardboad box underneath a fleece blanket (the kind you use to keep warm), in a fridge in an open topped bag. They will just hibernate and won't start to sprout for a long time. This is how I store seed potatoes that I buy in spring, to plant out in June/July. It's a good technique to use when you don't have cool/light space for chitting.
In a cool place, in the light
When you do this the potatoes will start to sprout, which is called chitting and the subject of the next section.
Chitting is a very useful technique to get your potatoes primed for growth. A chitted potato will start growing the instant that it's planted. This is very useful for early potatoes, because they get started faster, but they also start growing much more predictably and that's very useful if you have limited growing space, you know where you are in terms of your plan. Chitted potatoes can also sometimes provide a slightly higher yield, but it's not that significant.
Chitted potatoes, with spruts at the ideal size for planting
Here's a few more tips:
Chitting tubers makes timing more predictable
Although almost everyone chits their early potatoes (there's no advantage to chitting main-crops) planting them indoors makes a bigger difference. While a potato might take a month to surface outdoors in the cold soil of mid-spring, it will break surface in just a few days indoors. That's nearly three weeks earlier that outside. Combine that with the other techniques I describe and you get potatoes more than a month early.
In my experience the most useful thing about chitting is you know the tuber will start growing immediately after planting. This makes timing much more accurate.
Although starting indoors is a great technique, the 20-35 litre containers that I use take up a lot of space. Also they are heavy and difficult to move between the house and the allotment's polytunnel. It's much easier to start the potatoes in smaller plant pots. The additional advantage is that these pots also fit under (or next to) my grow lights.
The pots I use are 2L and they take up 1/3 of the space that the large tubs they will grow in in take up.
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Start potatoes in small pots, this is 9 days old
Smaller pots allow the plants to stay indoors for longer and grow strong root systems early in their lives, because they get bright light on their leaves sooner.
Finally it's easier to transport these smaller pots to their final growing location. Just loosen the soil in the pot and tip it upside down, while holding the top of the pot with your fingers, the plant should come out easily. Take care not to let the shoots grow too long though, otherwise you risk breaking them.
Finally bury most of the plant. This ensures that you wont have two many potatoes near the surface going green. If you do get green potatoes consider savings them for next year’s seed.
If you start in plant pots indoors you don't need to bother with chitting. Comparing chitted to unchitted potatoes they broke only 1-2 days earlier.
I start most of my seedlings, including early potatoes, inside. My conservatory is frost free and usually above 11c at night and much warmer during the day.
Grow lights are too expensive to buy to grow potatoes, but if you have them for your high value crops you might find that you have spare capacity early in the year. In my case I don't, but I can use the spill-over light. Next to my grow light is 2/3 of the intensity that plants enjoy directly under the lights, but that's enough for large leaved plants like potatoes, at least for a few weeks. This combination of reasonable light and warmth is worthwhile if you want super early plants like we do.
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Potatoes taking advantage of 'spill-over' light from my conservatory grow lights
Early potatoes need to be grown under cover. A sunny conservatory is ideal, but in my case all the sunny spots are soon occupied by tomatoes and peppers, which need night time temperatures above 50f/10c. Potatoes can cope with the cold better, so they go in the greenhouse/polytunnel. They will need protecting from frosts there, so keep a double layer of fleece ready at night.
Polytunnel potatoes under fleece (single payer in this photo)
The fleece can be left on during the day too, but light levels are lower in March and April, so remove it if you can.
General advice on growing potatoes in containers
General advice on growing potatoes in containers
I have a lot of patio space available for containers and I like to have the space full of lush growth. Of all the options for container growing, potatoes seem best. They take up 1/3 of the space in a container that they do in the ground, so they are very space efficient and it's relatively easy to water them too. The other benefit of containers is the ease of harvest.
However I do find that I can grow early baking potatoes more reliably in my deep cold-frames, which I describe later.
Potatoes need plenty of water once they really get going, so we try to water at least once a week (more in mid summer) until we see water coming out of the drain holes.
For salad potatoes we normally leave them in their containers, sometimes for as long as six months, but we move the containers into our little greenhouse, so we have no frost/slug damage and the compost is moist, not sodden.
We normally eat the skins of our potatoes, so we wash them after harvest. We carefully lay them out on the grass and give them a spray with the hose, taking care not to damage the skin. If we are storing them we lay them out in shallow cardboard boxes - 1 layer deep - from the supermarket.
We then leave them in the fresh air and sunshine for about 24 hours, if it's raining they sit on the dining room table instead. We will turn them once or twice to make sure they are really dry.
Potatoes in their shallow storage boxes
Once fully dry we move them - in the same boxes - into the garage, which is fairly cool and frost free. They are stacked on shelves and covered with thick fleece blankets.
We used to store them in sacks, but we found it hard to rummage around to find the sizes we wanted for a particular meal and much harder to spot rot or other issues.
We also keep a mouse trap on each shelf in the store, with dry cat food as bait (it lasts a month or so, unless it's eaten).
How we store potatoes and other fruit and veggies
How we store potatoes and other fruit and veggies
There are so many varieties of potatoes, it's hard to get you head around all of the options. For the purposes of this guide I'm going to keep everything as simple as possible. Because of the way I grow, the usual definitions of first earlies, second earlies and main-crop are not very useful.
We like Swift, Arran Pilot and Charlotte. I've chosen these three because of their versatility, Arran Pilot and Charlotte are also great as baking potatoes (see later), Swift is a fast grower and Charlotte is a good general purpose potato and it keeps well.
We like Charlotte, Cara and Sarpo Mira. I think it's very important to have some potatoes with very good blight resistance in the mix and of course potatoes that keep very well.
We like Charlotte, Cara and Sarpo Mira, but we are replacing Sarpo Mira this year with Estima. Arran Pilot are first earlies and hence it's very strange to think of these as baking potatoes, but planted at the right time, they make great, very early, baking potatoes. They don't keep very well though, so harvest a container at a time. Also be sure to follow them with a second early like Charlotte/Estima that keeps really well. A few weeks later you can then plant your traditional baking varieties Cara and Sarpo Mira, which have good/excellent blight resistance.
Charlottes on 20th June
Start by finding out when your sunniest months are, this is the site I use. The chart below is for Blackpool Airport, which is a couple of miles away from where I grow. Potatoes are a cool weather crop, but they like the sun. Looking at the chart it's easy to see that April and May are very sunny in St Annes, as sunny as June and sunnier than July.
Traditionally potatoes would be planted out from early to late April, they won't break surface outside until May and they won't have a lot of leaf area until June. As a result they miss two months of sunshine. To grow early potatoes we need to take maximum advantage of the lovely sunny months of April and May. To grow really early potatoes you need to take advantage of March as well.
Although April and May are lovely and sunny, they are also cold, so protection from frosts is critical, but so too is maximising light levels during the day.
Similarly you can see that July, August and September are very sunny. If you grow early potatoes for harvest in June/July then you can use the same space to grow late potatoes in July - September.
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Depending on the type of potatoes you want to grow there are quite a number of options available to you. These are the potatoes we grow, you can pick and choose or modify the list to suit your own requirements.
Note that although the following sections talk about salad potatoes and baking potatoes, some of the harvest will of course be medium sized, general purpose potatoes, but since you don't need any special techniques to grow these I don't bother to mention them again
Growing potatoes late is easier than growing them very early!
Growing potatoes late is easier than growing them very early!
Although it's possible to grow very early potatoes to harvest in March and early April by planting in December/early January, I don't normally recommend it, the yield is very low. I prefer to grow late potatoes, in containers, started in July/August and then keep them in the damp compost (we keep ours stacked up in the greenhouse) until we need them. They keep well until early April (when they start to sprout) and have a lovely freshly picked taste, even six months after the tops have died back.
Growing very early potatoes like this has several advantages, compared to potatoes started in December/January
I prefer growing these late potatoes in compost and containers because I like to keep them in the compost until harvest time. I like to start mine in July because they stand a better chance of growing to maturity before blight stops them in their tracks. August works too though. If you have space in a greenhouse/polytunnel you have the option of moving them under-cover in September/October, slightly reducing the risk of blight.
If you do get mild blight start by picking off the affected leaves, this often allows you to get a few weeks of additional growth, which makes all the difference to the yield. At some point you will feel like you are losing the battle, especially if the stem is in any way affected. At this point just pull out the stems and leave the potatoes in the compost until needed. I've always lost my late potatoes to blight, but I've never had a tuber affected, even on potatoes that finished in October and were harvested in April.
One of the challenges when growing very early potatoes is getting seed potatoes in time as they are not available to buy. For the very earliest crop you really want to chit them in December and plant them in January, using the techniques I describe later. This is especially tricky for varieties like Arran Pilot, which make excellent large potatoes (given enough heat and light) in only 90-100 days. However they are usually grown as a first early and they might not keep until December.
What to do? Right now my only idea is to grow a second batch, using the seed potatoes from the first batch, but planting them in July/August. Now the issue with this is that the harvest from the first batch will still be dormant in July/August and won't start growing. So I need a way to break dormancy.
I've come across a research paper that explains a technique for breaking dormancy, which I will include here, along with my variation of it:
After 7 days they should start to start chitting, or just plant.
Very early new potatoes
We really like to have salad potatoes for most of the year. We typically cook them the day before and allow them to cool in the fridge. This way some of the starch converts to - super healthy - resistant starch. This is how I grow them, step by step:
We normally run out of general purpose potatoes in April, so the race is on to get good sized (egg size) general purpose potatoes as soon as possible in May and June. We use Charlottes for this purpose (but we are also trialling Arran Pilot) and basically it's the same approach as for the very early salad potatoes just starting a bit later, leaving a bit longer and growing in larger containers. It's important not to start them too early though because they need the heat and light of April to grow to a good size. The objective is to have them in good leaf by April.
This is how I grow them, step by step:
My first try at baking potatoes in June, the method below refines this experiment
My first try at baking potatoes in June, the method below refines this experiment
We normally run out of baking potatoes in April, so we want them again as soon as possible.
<aside> 💡 For a while I didn’t think it was worth the effort to get them any sooner than the beginning of June, but I’ve changed my mid, see later.
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They need about 2.5 months of good sunlight, and they can only really get that in April and May, (they benefit from grow lights in March). Fortunately we have some spare grow light capacity in March, because the peppers and tomatoes aren't taking up much space until April. Our objective is to have two baking potatoes a week from June onwards, that means we only really need four 35 litre containers to go through this process. We use arran pilot for the first two containers and charlottes for the remainder.
How to Grow