SOIL CONTAMINATION BY POTATOES
The other big advantage of growing potatoes in their own
containers rather than the raised bed is concerned with soil
contamination. Potatoes are one of those vegetables where it
is essential that they are not grown in the same soil every
year.
In a normal crop rotation plan, potatoes would only be
grown in soil used for a previous potato crop every four
years. If you grow potatoes in the same soil more frequently
than that you risk them suffering from pests and diseases.
So, when growing potatoes in containers always use fresh
compost.
Incidentally, we also grow tomatoes in grow bags which is
simply a different form of raised bed. By doing this we keep
two of main culprits of soil contamination, potatoes and
tomatoes, out of the formal raised beds and therefore
significantly reduce the complexity of crop rotation.
WHY GROW POTATOES IN CONTAINERS
We have previously mentioned that potatoes in containers can
be moved around to maximise their exposure to sun, that's
just one benefit of growing potatoes in containers. The key
advantage though is that you can start potatoes in
containers off a few weeks earlier compared to those grown
in the ground or a raised bed.
The reason container potatoes can be started off early is
that if a frost threatens, the container can be moved to a
protected position until the risk of frost has passed.
Potatoes will grow even in cool conditions, albeit slowly.
But expose the foliage to even a degree of frost and it will
turn black. It is true that as long as the tubers have not
been frosted the blackened foliage will die off and new
foliage is likely to appear. But the potato crop will then
be significantly delayed. If the tubers have been affected
by frost then the entire crop can be lost.
WHAT TYPE / VARIETIES OF POTATO FOR CONTAINER GROWING
This can be a complicated if you want to have potatoes over
a long season. However, if this is your first year of
growing potatoes in containers then choose one variety of
"early" potato and one "maincrop".
If you really want to have potatoes over a long time and
continuously then below we give the planting to harvesting
times for the key groups of potatoes:
FIRST EARLIES
The quickest potatoes to mature. They take anywhere between
60 to 105 days from planting to harvest. How quick they
mature depends on the weather conditions and the variety.
Most will mature in 80 to 90 days.
One very early maturing variety which we recommend is
"Casa Blanca". Ready for harvest in around 65 days / early
to mid June. Lady Christl is another good one which matures
in around 70 days / mid to late June. Lady Christl has been
awarded an AGM by the RHS which confirms its all round
excellence.
SECOND EARLIES
The medium season potato type which will take 105 to 120
days from planting to harvest. As far as particular
varieties are concerned we leave it up to you to choose. Our
firm favourite for general kitchen use is Kestrel.
MAINCROP POTATOES
The take the longest to mature but they produce the largest
crop and they store much netter than early potatoes. Many
people say that it is pointless growing your own maincrop
potatoes because the shop bought ones are so cheap. That may
well be true but grow your own maincrop potatoes and you
know exactly what they have been sprayed with - nothing! The
simple joy of eating your own home grown potatoes is good
for the soul, whatever the economics.
Maincrop potatoes take between 125 to 140 days from
planting to harvest. There are endless varieties so choose
one that suits you. We regularly grow Maxine as a maincrop
but that's only our personal choice.
CONTAINERS FOR POTATOES
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The choice of containers for growing potatoes in is almost
endless. Type in "potato container" or "potato grow bag"
into your favourite search engine and the options returned
are bewildering.
The key requirements for a
container to grow potatoes in are that is has
drainage holes at the bottom, it is big and deep
enough to produce a meaningful crop from at least
one seed potato and that the sides can retain the
compost. |
The shape (round, square even triangular) is irrelevant.
The size can range from a large pot 20cm wide by 30cm
deep up to a large dustbin sized container. It all depends
how many potatoes you want to grow and how much space you
have available for growing potatoes in containers.
Our particular choice is a reinforced plastic type bag
(see the picture) which is about 35cm wide and 70cm. That's
enough for two or three seed potatoes and we can still move
it relatively easily. We use three of these at any one time.
COMPOST TYPE
Use general purpose potting compost for growing potatoes in
containers. Yes you can use John Innes type composts or a
mixture of the two but we have not found that it improves
our crops. Never use garden soil for growing any plants in
containers.
NEXT STEPS
Now you know the advantages of growing potatoes in
containers it's on to the business of chitting and planting them, caring
for them and harvesting them. Either click on one of the
headings below to go straight to that subject or click on
"next potato page" to read the next page in this series on
growing potatoes in containers.
HOW TO CHIT / SPROUT POTATOES
PLANTING POTATOES
IN CONTAINERS
CARING FOR POTATOES IN CONTAINERS
HARVESTING POTATOES IN CONTAINERS
HOW TO STORE
POTATOES
GROWING POTATOES
IN CONTAINERS FOR CHRISTMAS
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ANSWER: Almost certainly your potatoes had scab which is cosmetic only and does not affect the eating quality of the potatoes.