Medlars, mildews and mulching
It looks like we will be frost free for another week while we enjoy this unseasonal warm air that’s moved north from Europe, alongside the occasional deluge of rain. But before I dig into my 3 Ms, here’s a bit of a climate update.
On track for 3 degrees?
Next month, Baku hosts the COP29 and ahead of the conference there has been a flurry of pretty dire updates. Back in 2015, the Paris Agreement set a goal for the world to limit global warming to just 2C above pre-industrial levels and to do that it would require the world cutting emissions by 43% by 2030 and 60% by 2035, compared with 2019. To limit global warming to 1.5C, greenhouse gas emissions had to peak before 2025. Well, thanks to the world’s continued desire to burn fossil fuels, cut down forests, dig up peat, plus wild fires, carbon emissions actually went up last year by 1.3%, thats +2.3 ppm, and the UN fears that we are more likely to be on track for 3C by 2100, unless we really up our carbon-cutting game.
I really wish our global leaders would actually listen to the experts - it is still possible to transition to net zero in time and the really, really, really stupid thing is that it is cheaper to act now. UNEP experts say that we could avoid the worst of climate change by spending a mere1% of the world’s total economic output and get to net zero by 2050.
Instead, governments seem happy to shell out billions and billions of dollars each year to repair the damage wrought by extreme weather events and that doesn’t take into account the human suffering that these events cause, the rising sea levels that are destroying island nations and more. Let’s hope they wake up in time.
But on a brighter note, the EU has cut its gas demand by as much as 20% since 2022, reducing its reliance on imports. Denmark, Finland, and Lithuania have halved their demand and across the bloc, renewables have surged ahead, especially in the Nordic countries, while outside the bloc, Norway uses almost 76% renewables. The rest of the world needs to catch up!
Back to gardening in an uncertain climate ……
Medlars (Mespilus germanica)
I’m sure you have been reading about medlars elsewhere. These weird looking fruits are quite photogenic in their own way, and I love that hollowed out top is often home to minibeasts like ladybirds and lacewings. They were described as ‘a dog’s arse’ by Shakespeare, while D H Lawrence called them ‘autumnal excrementa’, so not that appealing! Depending on the variety, they can be pear-shaped, round, or flat and up to 7 cm in diameter.
They are fascinating fruits that came originally from the Black and Caspian Sea region. They were traded across Europe, reaching Britain back in the 13th century when they were grown in abbey orchards. Due to the sweetness of the ripe fruits, they were much desired treats, so by the 19th century, they were grown across southern England. But since then, their popularity has waned, mostly because of the time-consuming process of ripening them called bletting. Bletting is not the same as rotting. Its is a natural process that takes place inside the fruit as cell walls break down and sugars are released. The result is a sweet and juicy pale brown pulp, not that dissimilar in taste to a spicy, cooked apple. I love making medlar jelly, but I also reserve some to make a medlar sticky toffee pudding in which the medlar replaces dates, so its a really scrumptious and sustainable alternative. Mark Diacona has the perfect recipe which you can find on his Substack
Why am I growing more of them? They have a low chill hour requirement so are a perfect option for my climate change orchard. I am looking to add the Iranian medlar to the Nottingham variety that I am growing at the moment. Medlars also add diversity to the orchard which is also a good thing. Keepers Nursery in Kent has a great range, but they are selling out fast.
Mildews
It’s been a bad year for mildews, given the humid weather which we have seen his summer. There are two forms, downy and powdery mildew, and they are favoured by slightly different conditions. Downy mildew is caused by oomycetes (Peronospora sp.) which are related to fungi. They appear later in the season and love warm, wet weather and heavy dews. The first signs are yellow patches on the upper leaf whiuch get larger and turn brown.
Powdery mildew is caused by a range of fungal species, each being specific to a different host. This mildew doesn’t like heavy rain, instead it thrives in warm, dry conditions during the day and high humidity at night for spore production. The first signs of a problem are grey patches appearing on the leaves. Powdery mildew poses a huge threat to vineyards across the UK and Europe, as even the slightest infection on the fruits can taint the wine, while loss of leaves causes a reduction in yield. The varieties of grape vary in their susceptibility. In the UK, Bacchus grapes are particularly affected, while Regent is quite mildew resistant due to its American vine ancestry. We get powdery mildews in the garden too, especially on courgettes in summer.
For those growers who manage their vineyards organically, fungicides are not in their arsenal. Instead, they have to turn vigilance, natural sprays and biocontrols. Air flow is important so stripping back the canopy to improve the air flow plus removing the infected leaves. Some use a biocontrol called Amylo-X (Bacillus amyloliquefaciens subsp. plantarum strain D747). The bacteria colonise the surfaces of the leaves and secrete antifungal compounds that reduce the ability of the spores to get established, enhancing the plant’s resistance to pathogens. Trials of the bacterial spray has been found to control powdery and downy mildews and Botrytis.
Interestingly, SB Plant Invigorator used by many gardeners acts in a similar way, and in some vineyard trials, its used as part of the preventative programme. It is thought to act by degrading fungal hyphae and spores.
Another option is the biodynamic approach which involves sprays based on horsetail, yarrow and essential oils. The idea is that the sprays alter the surface pH of the leaves making them inhospitable to spores. Also, the horsetail is high in silica so tends to dry out the leaves and discourages fungal growth, while yarrow is high in sulphur (a well known treatment for mildew) which deters the fungi. These sprays have to be freshly made up, seeping the ingredients in hot water for a few hours, then spraying over the leaves. I have horsetail growing on the farm, so I harvest it regularly and dry the leaves for later use. You can read more here in this fascinating blog from Limeburn Hill organic vineyard which gives advice on how to make your own spray. The vineyard is near Chew Magna near Bristol, just up the road from my favourite organic garden at Yeo Valley and they have tours and tastings.
There’s more about natural sprays in my recent book, The Resilient Garden and Allotment Handbook which you can buy online.
Mulching
It’s that time of year we’re are all (I hope) collecting fallen leaves to compost and mulch our flower and veg beds. Much is written about the importance of mulching in early summer to reduce the evaporation of water from the soil, but its just as important in winter to protect soil from raindrops. The impact of raindrops can actually seal the soil, creating a smooth surface which encourages water run off and leads to soil erosion, while the presence of a mulch creates a rough surface that helps water to sink into the ground. It’s a classic method to slow the flow of water. In addition, it helps to reduce the germination of weed seeds, and keeps the soil warmer which is so important for our overwintering dahlias, cannas, gingers etc. A mulch of fallen leaves can also provide an important habitat for our predators, such as centipides and spiders, as well as provide a safe overwintering spot for butterfly larvae and pupae.
There is so much information on mulching that I’m writing an indepth look a the theory behind mulching and what mulches to use in my first monthly newsletter for paid subscribers. The first one, to celebrate my first year of ‘Substacking’ will be published on 1 November. I have kept the rate of a paid subscription to just £25 a year, that’s the cost of a pack of organic seeds a month, so I do hope you might be tempted to join the growing number of paid subscribers. But the free weekly newsletter will continue to pop into your inbox weekly and I would be delighted if you would share it with your gardening friends.
Happy Gardening
Sally
PS If you have enjoyed reading this post, it would be great if you could click the like button below. And please do share with your friends.
Talks
I am talking at a number of venues in the coming weeks. Most of these clubs allow non members to attend for a fee.
19 November Mayfield Horticultural Society by zoom
21 November University of Bristol Botanic Gardens
23 November I am talking at the inaugural LandAlive conference at the Bath and West showground on Sat 23 November. The topic is on creating a climate resilient allotment.
4 December Castle Cary Gardening Club