Tuesday, 21 February 2012

Tips for increasing potato yields

The PeopleWhen at potato day at the end of January, I picked up Alan Wilson's new book, The People's Potatoes. I've already written about the engaging talk he gave on 20 Challenges and Opportunities for Potatoes, which he also talks about in the book. The first half of the book includes interesting chapters that cover topics from understanding the biology and growth of potatoes, the production of seed potatoes, chapters on both commercial and home/allotment potato growing, and one on pests and diseases. The second half of the book goes on to detail Alan's top 100 potatoes, then a reference section covering a further 300 potatoes also grown in the UK.

It's great to have the reference section and detailed listing of so many potatoes as it is not easy to get this information in books generally, or even by searching the web. I can see that I'll be referring to this section regularly to get more information about the potatoes I grow, or might grow in the future.

The book also contains some wonderful tips for growing potatoes and increasing yields. It goes beyond general advice you usually get, such as remembering to earth up your potatoes and when to dig them up. Below is a summary of some of the key points (in my opinion) from the book that should help increase your potato yields.

1. The most productive potato plants are those produce a good leaf canopy, and the longer the leaves remain, the higher the potato yield. I found this interesting as we are often told you shouldn't feed potatoes nitrogen as it will just encourage leafy growth at the detriment of the potatoes in the ground. BUT, as the book says, a good leaf canopy means there is more area to intercept light, which via photosynthesis is turned into energy for the plant. This helps it develop good roots systems that extract the water and nutrients needed to increase yields.

2. Stem numbers are key. That is, the more stems that come direct from the ground and form a leaf canopy, the higher the yield. Stems that grow direct from the seed potato you planted are 'main stems' and these usually produce tubers. So the more main stems, the more tubers. Stems that branch off from the main stem are 'secondary stems' and these don't usually produce tubers unless the branching point is close to the seed potato. That is, the branching out happens quite low down at the base of the plant.

3. Watering. The key growth stage for potatoes is usually 3-4 weeks after a plant has first emerged from the ground. The plant sets tubers at this early stage, so a lack of water or soil moisture at this point will effect the yield. Potatoes of course need watering throughout their growth cycle, particularly in hot weather if you are to maintain yields. But it's particularly important that they are well watered at this point if you want your potatoes to set more tubers. And don't forget that the more organic matter your soil has, the more moisture and therefore the better chance of increased yields.

4. Foliage die back. When the foliage starts to die back, the plant is coming to the end of its life cycle. But where the foliage starts to die back is very important. If the dying back starts at the base of the plant and moves up the leaf canopy, you should have healthy tubers. However, if the lower leaves are healthy but the upper leaves are turning yellow, it may be the plant is suffering an attack from a pest or disease, or lacking nutrition.

5. Digging up. Don't start digging up all the tubers as soon as foliage starts dying, unless you intend on eating them all fresh! As the plants die back, tubers start to form a skin, called setting a skin. This helps the tubers to develop a protective layer, which is particularly important if you want to store your potatoes for any length of time. You need to allow 2-4 weeks from when die back begins before digging up the crop that you intend on storing. Allowing the tubers to set their skin helps prevent water loss, stops tubers from going soft, and reduces the risk of disease. So, for fresh earlies, harvest whilst the leaves are still green. To store, wait for the skin to set.

6. Inside the potato. Generally, though not always, lower dry matter (i.e. less than 20% starch) is typical of earlies, and usually (but not always) produces smooth waxy potatoes that are good for salads. Potatoes with a higher dry matter content (more than 22% starch), produce more floury roast/baking potatoes. For boiling potatoes, avoid using high dry matter varieties. Or if you do boil them, do so for less time, so they don't break up.

The book goes into more detail than I have here, but hopefully it gives an indication of it's usefulness. I learned a lot of new things about how to grow potatoes, and also the reasons why you should do things a particular way.

I recommend this book to anyone who enjoys growing and eating potatoes. It's intelligent and engaging, and I expect my yields will be increasing this year. And that makes for a happy belly.

Sunday, 5 February 2012

Garden visit: Anglesea Abbey (2nd visit)

The winter walk includes many trees and shrubs that
give wonderful winter colour:
hamamelis, cornus, viburnum, betula and prunus

Anglesea Abbey is well known as one of the best winter gardens in England. I've visited before and I'll visit again. This years visit, yesterday, was as lovely as always. It has to be said that the sudden freeze had meant that the poor snowdrops have been hit, and whilst they were flowering, quite a lot were laid low by the cold weather. But there is so much to enjoy in the winter garden and by the Lode mill, that you don't just go for the snowdrops. My visit in pictures...

hamamelis, with cornus behind

The lovely bark of Acer griseum

Galanthus 'Ophelia'

Galanthus 'Merlin'

Galantus 'Galatea'

The beautiful shiny bark of Prunus Serrula

Birch grove, betula jacquemontii

Canal by the Lode Mill

Reflections of the Poplars in the ice

Young Miguel cannot resist testing the icy canal, with parents Patrick and Lyn 

L-R: Audrey, Lyn, Patrick, moi, Kevin

Thursday, 2 February 2012

First day of the month in the front garden: February 2012

Ok, slight cheat - it's the 2nd day of the month. Does the fact I did my back in yesterday give me any grace?

Front garden, 1st (ok, 2nd) February, 2012

Early February in the front garden. After January being so mild for most of it, the sudden cold has slowed things down a bit. However, compared to the greyness of January's post, the lovely colours of a cold and sunny February makes it worth it.

Broad beans coming up

Not a lot has changed, other than the broad beans I planted in the right side bed have sprouted where there were nowhere to be seen in January.

Bulb and iris leaves

I also have the leaves of various bulbs coming up, muscari and crocus, as well as some of the garlic. And the Iris leaves, which never completely died off this winter (unlike the previous year), are standing to attention and getting read to put on exponential growth the moment it gets warmer.

The first colour has arrived in the guise of one lonely crocus flower. Not even open, thanks to the freezing temperatures of the last few days. But that just makes it more welcome, more of a delight. Despite the weather it's keen to get outside and do its thing.

Now we wait to see if February remains cold and therefore growth is slow. Or will it suddenly warm and bring out not just the crocus but all the daffidol and narcissus flowers, but also the green growth of the fritillaries?