July 2016, potato flowering and blight, comparing dig/no dig, harvests then clear, replant 14


Looking back over spring, it started cold and then was good. May and early June growth was as fast as I have seen, until the wheels came off recently with the arrival of wind and rain. A British summer has installed and I feel less optimistic, slugs are breeding fast.

If the summer stays cool, dull and wet, it will highlight the importance of undug soil (good structure and drainage), together with sowing suitable varieties at the best time to maximise the season. Squash for example are at their climatic limit even in southern Britain, and want setting out as strong plants by the end of May. No dig helps because soil stays warmer under a dark, compost mulch, and also because capillary conductivity remains unbroken, so that warmth (and moisture) from deeper levels can move freely.

No dig

A friend pointed out the endorsement of digging in July’s Gardeners World magazine by Monty Don.  He makes it sound romantic, with no reference to the destruction of soil life.

I think he personally likes no dig, but his job involves writing for diggers too. Or perhaps he does think digging is worthwhile, its hard to know! Meanwhile some inaccuracies are frustrating, especially his claim that “If you make raised beds you have to dig the ground initially”. No wonder people get confused.

Below are images from Homeacres, all weedy pasture 40 months ago when I arrived. 

The soil has never once been dug or disturbed, two beds/strips excepted. 

Now its a productive and easy to run garden which also demonstrates how beautiful a vegetable garden can be.

Dig, no dig comparison

its ten years since I started comparing and harvesting the same vegetables in dug and undug beds. Mostly there are few differences, for all that effort of digging. But there is usually more weeding needed on the dug bed, while undug beds hardly grow a weed after May, once the weed seeds in its surface compost have germinated.

Harvests so far in 2016 are intriguingly similar at 35.73kg dug and 35.40 undug, and include potatoes 6.51kg dug and 5.86kg undug, carrots 2.24kg dug and 2.64kg undug, cabbage 4.84kg dug and 5.06 undug, peas 1.88kg dug and 1.67kg undug.

New plantings include cucumber, swede, kale and French beans.

Harvests of early summer

There is plenty to eat now and already its time to be putting vegetables by, such as garlic. Softnecks want to be harvested now, if you have not already, and hardbacks by mid month. Its only a fortnight until second early potatoes such as Charlotte can be gathered, and they can store until next April, make sure tubers are dry and keep them in paper sacks, frost free.

I have been impressed by Cabbice cabbage (Mr Fothergills), sown in February and planted late March, fleeced over for a month against cold winds. The heads weigh over 2kg (5lb), taste great, and have matured before the butterflies are numerous, so I have not needed to cover them. Same story for early calabrese. The Cabbice came from Delfland nurseries who sell a good range of vegetables for summer planting, use this link and code CD16F for cheaper Cabbice plants – one free pack per household, you pay postage £4.95.

Clearing and replanting, resowing

Many second crops are possible when you can be prompt with clearing vegetables that are finishing. For broad beans I often remove them (cut at soil level) when there are still a few pods on, because there is such abundance now that a few extra beans are less valuable than some space to plant. This also means that more nitrogen nodules are left in the soil, before the ageing plants can use them up. 

Crops to clear through July include lettuce, peas, beetroot, carrots, spring onion, shallot, and onions after mid month.

New sowings include lettuce, endive, chicory for radicchio, spring onion, carrot, beetroot (asap for these two), coriander, Florence fennel, kale and purple sprouting broccoli for spring. Sowing undercover gives more chance of plants getting away from slug damage. And keep on top of weeds, sow and plant into a completely clear surface.

Cleaning soil, new beds, mulches for paths

These different topics all come down to the two main things needed for successful vegetable growing: high fertility and few weeds.

Under the green polythene, weed-suppressing cover is a three inch layer of 50% homemade compost, 50% two-year-old cow manure. There is also plenty of field bindweed and some couch grass at one end, now dying from lack of light while the squash plants are growing.

The new beds next to it had polythene over the weedy jungle in February, then we removed the polythene and mulched with six inches compost in April between the temporary wooden sides, which are old fence posts: I remove them in autumn. 

In the paths, under the mulch of shavings is a thick layer of cardboard. Some couch and bindweed still needs pulling, regularly, where it appears through the planting holes and a few gaps. 

After this first year of heavy mulch, which leaves almost all perennial weeds dead or at least in abeyance, its generally possible to mulch with compost only, and have few slugs.

When to harvest potatoes

Another myth abounds and confuses gardeners, “that potatoes need to flower before harvesting might be good”. Such statements are misleading because it depends on potato type and variety. Many first earlies do not flower and the signal for harvesting them is leaves going yellow, best pull tubers before half yellow. Now if you have not already.

I am noticing this year that some bought Charlotte seed (second early) is not flowering, while plants from the home-saved Charlotte are in flower. No idea why but I shall harvest them all when leaves are about a quarter yellow and tubers are swelling above ground. I need the space for leeks, by mid July. 

If the leaves suffer blight, harvest will be earlier. When you see the first blight, unless its become fine weather again, I reckon to cut off haulm to  ground level, compost all the tops (that is another myth, you can compost them (see below)  and I recommend to harvest asap after blight appears.

Update 7.30am, June 30th: since posting this a French friend Nicolas Rouchon-Roche (no dig grower in S. France) sent this helpful comment: “the head technician working at Desmazieres (company creating new potatoes varieties like Cerisa) told me flowering potatoes was not a healthy sign, as gardeners usully think. When a tuber plant goes fine, it generally does not flower (depending on variety also) as its reproduction is done by tubers. So flowering occurs if drought, disease or something bad happens. He also advised that home made seeds are best kept at 4 to 5 degree celsius, witn no variation in temperature at all”.

Interplant ideas

There are many possibilities but you need to be organised about timing and spacing. The spring onions below are an option between celeriac, both planted at the same time in May, because they can use the wide space before it closes – which is soon: we shall harvest these spring onions over the next fortnight.

Possibilities for July include planting coriander with new broccoli, beetroot between maturing onions and sowing carrots between finishing leaf lettuce – though watch out for slugs on this one.

Its also a good time to think ahead and order apple trees for planting this autumn/winter. My one year trees cost just £10 from Walcote Nurseries and ordering early gives you more chance to buy the varieties you want.

Composting blighted plants Phytopthera infestans and other myths

Blight spores cannot survive in soil or compost, see this link http://www.bbc.co.uk/gardening/advice/pests_and_diseases/identifier.shtml?blight  – and this https://ag.umass.edu/fact-sheets/late-blight-on-tomatoes-potatoes. The latter mentions a difference for the southern USA where blight spores can survive in soil, but they do not in northern latitudes including the UK.

Unfortunately confusion arises because the RHS advises that “Infected material should be deeply buried (more than 45cm deep), consigned to the green waste collection or, ideally, burned rather than composted”. The links above, and my long experience, show that this is wrong advice. Also its environmentally destructive.

On a different topic the RHS advises that digging is necessary before planting asparagus and that it requires fertiliser each year https://www.rhs.org.uk/advice/grow-your-own/vegetables/asparagus. My asparagus disagrees on both counts.

I find it frustrating that gardeners are often advised to do unnecessary work, spend unnecessary money and do unnecessary harm to the soil and soil life. For example the peas you see below have been so easy to grow, just mulched with compost, in soil that had bindweed and couch grass three years ago.

So don’t believe everything you read or are told, ask for reasons if something seems wrong. Be sceptical of my writing too, but its all based on garden experience and the growth you see here.

Pests

The annoying part of gardening. Its not butterflies this summer but slugs. Reducing habitat is key, traps, wool barriers, sorties at dawn and suk with a knife or bucket. Its ongoing, no easy answers, avoid mulches of unrotted materials.

Now at Homeacres I have a tame, young rabbit who loves lettuce seedlings above all. So more plantings are netted than normal, and sometimes the rabbit slips underneath. Larger plants are left alone.


Leave a comment

This site uses Akismet to reduce spam. Learn how your comment data is processed.

14 thoughts on “July 2016, potato flowering and blight, comparing dig/no dig, harvests then clear, replant

  • Steve J

    Hi Charles great to read your comments. Regarding potatoes, I decided that this year I would grow them in pots. I thought they would be cleaner and the ground under get a rest. I filled the tubs with compost scraped off the bed, supplemented with a compost, old horse manure, leaf mould and any old compost from emptying plant pots. The potatoes are fantastic averaging 750 g per pot and the resulting compost is after emptying the pot is put back on the bed. Happy gardening

  • Lottie

    Hi Charles
    Thank you so much for these bi-monthly updates. They are very much appreciated!
    I am just curious about your apple trees. What varieties have you got and are they dwarf trees as they seem to be spaced not too far apart?

  • charles Post author

    Thank you both for your appreciation.
    Steve, that is a happy result! thanks for sharing it.
    And Lottie, my trees are on M26 and MM 106, so medium vigour. Yes they are quite close in the line, but have loads of space either side so can root a long way there. Also I am keeping them shorter/smaller by summer pruning, cut off about half of this year’s growth, now!(Also thin fruit) More on that in my next update.

  • ullak

    I mulched my whole vegetable garden with straw two years ago. Last year a had an infestation of slugs (something unheard of in my area), but this year not. Maybe a fluke, but now almost every time I go into the garden I see a lizard (and once a snake), so I’m thinking maybe they are getting rid of the snails, having a great time under all that straw.

    • charles Post author

      Ullak I am glad its working for you, though I do not recommend straw for veg because of slugs. I guess your climate may be drier than here in the UK, where mulches of compost work well and do not encourage slugs. Nice to hear of lizards and snakes!

  • Nick

    Interesting to read about potato myths re flowering and blight. We have confirmed potato blight here in South Wiltshire and the talk on the allotment is along the lines of not composting and not being able to grow potatoes in the same place for at least 4 years. I am working on a 3 year rotation so hopefully won’t be a problem based on reading the very useful links. My first and second earlies have grown well, so the blight is not an issue, but my main crops have been decimated so will not amount to much. Apart from the Sarpo Miras that is, which are standing defiantly against all that the blight has thrown at them.

  • charles Post author

    Good old Sarpo Mira. Research on that was funned by a pittance.

    You can grow spuds next year in soil that grew blighted ones this year.
    It grieves me that so many gardening decisions, and complications, arise from misunderstandings. Science says blight does not survive in soil.
    Its like its kind of easy for fears to be exaggerated by suggestion.

  • Suffolkbeeman

    I have been no dig for over 30 years and tend to agree with most of what appears in this blog. However I wonder if a test of Charles no dig system on what was previously intensively farmed land that had 40 years or so of inorganic fertilisers and weedkillers applied which is what most new housing estates are build on as apposed to a nice meadow which is where Charles created his no dig. Wouldn’t we all like a noce meadow to create a garden, dig or no dig!

    • Steph

      I see your point about the horrible soil offered as gardens on new housing estates, but wouldn’t describe the garden as a ‘nice meadow’ – it was weedy pasture infested with couch, bind weed, creeping buttercup, creeping thistle and other weeds. There’s a lot of concrete/hardcore too, an unexpected discovery which meant the new greenhouse and polytunnel had to be relocated,where greenhouses stood in the 1960s, goodness knows what else as the greenhouses fell into disrepair and collapsed: broken glass too, probably. We had to take down fences, remove junk, parts of it resembled a muddy nightmare with churned up soil, there was a huge pile of old ash from fires, it was quite disheartening at times.

      Charles has set up two gardens previously on very compacted clay – for decades by farm machinery.

      My own garden (an old council house, so nothing fancy) has one area which is builder’s rubble from the 1970s, containing a special kind of ninja bindweed. Almost of the other areas I grow on, except where the polytunnel is, were covered in rickety sheds (some made from asbestos) and the soil was very compacted. The area nearest my back door had a large climbing frame on it – 20 odd years of children jumping up and down on that compacted it very thoroughly. I have some very ugly concrete areas too, which I have had to just decide to cherish and love (and put pots on!)

      So not 40 years of chemical abuse although it was most certainly treated with chemicals up until 16 years ago as the owner then used them a lot, but I should think comparable with some of the difficulties faced with new gardens in modern estates.

  • charles Post author

    Thanks Steph for that. Suffolkbeesman, thanks for your comment and yes no dig works well in any soil or situation. For degraded soils you need a higher application of compost initially, which also applies if you are digging.
    Funnily enough I would say that no dig is even more applicable on worn out, difficult soil, than on a ‘nice meadow’.
    My biography, under Learn above, http://www.charlesdowding.co.uk/wp-admin/post.php?post=631&action=edit has more on my use of no dig over the years.

  • Rhys

    I can certainly add to the slug problem this year. The spring crops have all been great – over-wintered cabbage, garlic, early lettuce, broad bean etc.

    May saw no slug problems at all and I naively thought that I was on for a great summer. Sadly, June saw an absolute plague of the things eating everything in sight. Beetroot leaves repeatedly munched. Two sets of lettuces destroyed. Spring onions destroyed. Celery destroyed. Two sets of dwarf beans gone. Repeated problems with carrots. Much of it was sown in modules, planted out and looked to be doing great when the slugs arrived. Grr!!!!

    The garden looks a bit strange with magnificent parsnips, onions, potatoes and leek modules but everything else in real trouble.

    We had 6 inches of rain since the beginning of June – a pail filled to the top in one month. Way more than normal up here and most of it in very heavy showers.

    I can also report that it seems possible to grow early tomatoes to harvest in early July without having a greenhouse or polytunnel. Simply sow at the February full moon (Red Alert or Maskotka), put them outside as soon as you dare and reduce the watering by mid June. They work very well in 15cm pots – more yield for less compost but more faffing around watering them all. Three years running this has worked – in fact, I had Maskotkas in early June in 2014 sowing them at the beginning of February.

  • charles Post author

    Hi Rhys, that is bad news on slugs, so disappointing.
    Where are they hiding by day, is there any way you can find them there? Are you doing any dusk or dawn patrols? The rain in June came just ‘right’ for large summer slugs.
    On a much brighter note, that is a notable achievement on tomatoes, with minimal facilities. My greenhouse Maskotka are only just harvesting now, while Garden Pearl was earlier, and tasty too.

  • Milly

    As a newcomer to these posts,it is great to read all the tips. For some years I have wanted to recommend somewhere my best slug deterrent – bantams hens!
    I know large open ground growers would find temporary fencing of seedlings a fiddle, small raised beds and containers are little trouble. Back plastic on the soil before sowing salads brings up the slugs for the beaks to devour, and although I lost some early lettuce, I certainly ‘lost’ a multitude of pests.
    I would be wary of standard birds, but the light weight bantams do no damage and their free range eggs are terrific.
    Looking forward to future news and views now that I have joined the gang, and thanks for this great site.
    Milly