Potato Blight - my way of dealing with it
I keep a sharp eye out for potato blight now, as conditions will be ideal for its development over the next few days, with warm weather following the recent torrential rain. If you got your seed tubers in early by starting off 1st and 2nd early varieties off in pots, as I do every year now - you should already have a decent crop under them already though. First and second earlies only need 10-12 weeks to develop a reasonable crop - and obviously after that any increase in the weight of the crop is a bonus. If we get a dry early summer, unless it's very humid we may not get blight until July - but after that it's mostly a given! I avoid early blight every year using my 'pot-planting' method. I know a lot of people just can't get their head around starting off potatoes in pots because it's not the way things were always done. But why not? It's easy enough to do on a garden scale, and no different to planting lilies or dahlias! Many other crops are started off this way and people don't have a problem with that! With climate change we will have to learn to 'think outside the box', be flexible and adapt our methods if we want to produce crops without harmful chemicals - although even those are becoming less effective now. Even permitted organic sprays such as copper sulphate can be harmful too, and can build up in the soil if overused, particularly in clay soils. It's severely restricted now under organic standards. I've never used any sprays whatsoever here for blight on potatoes but still get good crops, by growing them my way.
Even early blight doesn't bother me now though - because in a normal year, all my potatoes are already flowering and developing their tubers nicely. I normally plant the outside crop in mid April in the way you can see here. They were all started off in early March and by then were already well developed plants with a good root ball. After planting I always give them a good watering and then a heavy mulch of grass clippings which keeps the moisture in and weeds down - making sure to leave the stems clear of mulch which could rot them. After laying down the mulch I then water again - to ensure that no fumes are given off as the clippings don't heat up - which can burn leaves. The heavy mulch seals the surface, blocking out light so that weeds don't germinate and also stops the water evaporating too quickly - creating too humid an atmosphere around the plants and possibly encouraging blight. I then don't water again until the flowers are open - because this is the time when they start to develop their tubers. Less watering means less possibility of encouraging blight - so the best time to water is when you know plants will need it most.
Blight spores are in the air everywhere all the time, waiting for exactly the right conditions - warmth and high humidity. Really good air circulation and low humidity conditions are the keys to avoiding it as long as possible. That, and growing more resistant varieties - like those pictured below - of which a few are being bred now. Sadly though they don't always have the wonderful flavour of the varieties I grow. There haven't been too many nights of frost since my potato plants were planted, so luckily I've only had to cover them a couple of times with a double layer of fleece to protect them from frost - there's no damage at all and they're growing really well. I always take fleeces off first thing in the morning as air circulation is so important to keep disease at bay. Despite hailstone the size of marbles in early May - there was no damage and they were looking really beautiful, but this morning are looking somewhat battered and bowed by the torrential rain overnight. They will recover though - but I shall now keep my eyes peeled for those first signs. Someone told me a couple of years ago about a really daft idea they had read somewhere - which was - "to cover the plants with polythene at the first sign of blight in order to stop it getting to the plants"! That's definitely the best way to reduce air circulation and the best recipe for encouraging blight as fast as possible that I've ever heard!! You can't shut blight out - any more than you can stop plants breathing!
|Innovator flowering - a blight resistant cultivar called Albert Bartlett Russet in UK||Naturally blight-resistant potato Vitelotte flowering||Potato Tibet flowering - the most blight resistant potato I have ever grown.|
As soon as I see any signs of blight on the Red Duke of York - always my best blight indicator, then I cut the haulms (tops) off all the plants immediately and cover that part of the potato bed with black polythene to stop any of the fungal spores washing down through the soil and rotting the tubers. Red Duke of York is always my blight indicator, being more susceptible than most - so it's always the first to be hit. After that I keep a careful eye on the other varieties in the bed and as soon as I see any sign of the 'tell tale' black blotches on the leaves, I do the same with them. Using this method - I've been growing enough potatoes to feed the family for most of the winter every year for the last 30 years or so - when I gave up direct planting of seed tubers at the traditional time of mid-March. Combining that method with my 'extra early' mid January planting of tunnel crops - which I wrote about earlier this year - it means that I usually have my own potatoes all year round, depending on how many of the family and friends there are here to eat them! If you're growing in raised beds as I do - you can even leave them in the ground for months then - they keep far better this way unless you have a massive slug or rodent problem. I don't normally lift the remainder of the crop until frost is a possibility, then I store them stacked in slatted plastic trays, in a cool frost-free shed, loosely covered with black material to keep the light out, but still maintaining good air circulation.
New strains of potato blight have developed over the last couple of decades and become far more resistant to the chemical fungicides used by conventional chemical farmers. This is why many non-organic, commercially grown crops are sprayed often 20 times or more with chemical fungicides - quite apart from all the toxic 'cocktail' of other chemicals they are treated with. These include 'dessicants' - like glyphosate-based weedkillers
I am also convinced that the amount of chemicals the general population is consuming now if they're eating these crops is going to cause a 'Tsunami' of health problems in years to come. Many scientists are beginning to worry about this issue too. Just this week some new evidence emerged about fungicides that are routinely used on many crops. Many think that fungicides are less harmful - but recent research has found that they induce changes in gene expression in mice similar to those in people with autism and neuro-degenerative conditions like Huntingdon's disease. This could partially explain the increasing incidence of such diseases. They're certainly not what I would want to eat - which is why I have grown all my crops organically for over 40 years, with no sprays whatsoever - not even organic ones like copper sulphate which are allowed under some organic guidelines! Growing potatoes my way, I find that I can grow enough potatoes to see us through the year without using any sprays at all. It's all a question of timing and TLC - but it's well worth it!
Keep up with successional sowing of salads - that's something that's so easy to forget when you're busy, but otherwise you can find you suddenly have a gap, particularly if we get another hot spell and plants go to seed. Even at this time of year I still sow into modules - that way plants are bigger, and much more resistant to the odd nibble from pests, or from bad weather..
The re-development of the kitchen garden into a raised ornamental potager is ongoing and the new, higher raised beds are a complete joy to work! Made from two tiers of 7 inch planks, so that even when my back is dodgy, it means I don't have to bend and I can even sit on a stool or chair to garden if necessary. It makes my heavy clay soil so much easier to work, and will improve as more compost is added over the years. The plan is to hopefully complete half the garden this year - another four beds, depending on finances and my son's goodwill! (he barrowed about 3 tons of soil per bed, from the top paddock to the garden bless him!). Possibly a little ambitious - but one has to have goals! We used 7 x 2 inch planks, treated with an oil-based organic wood preservative from Fruit Hill Farm, with corner brackets and 3ft/1m lengths of rebar hammered in along the sides at intervals for support, which looks very neat and they won't rot in the wet ground. I'm now making a carrot fly frame to fit over the bed and looking for some nice finials for the corners. I'm always looking for some new way to improve the garden - I'll never be bored!