Month: March 2018

Checking and Re-Potting Over-Wintered Dahlias

August 2016 Dahlia Esther Chamberlain
Dahlia ‘Esther Chamberlain’, a personal favourite

A timely reminder from Monty on last week’s episode of Gardener’s World sent me down to the greenhouse yesterday afternoon to check on our stock of over-wintered Dahlia tubers.

Dahlias are perennial plants that over-winter by storing sugars in large tubers below ground. But these tubers aren’t particularly frost-hardy or water-proof, so they do require protection to get them through the wet British winter. So they were dug up, dried out and potted up in spent compost last November, just after the first frosts killed off the foliage.

They’ll soon (hopefully) be bursting into new growth, which makes now the ideal time to check them over and make sure they’ve survived their winter hibernation intact. Here’s how:

1. Quick Visual Check

March 2018 Dahlia tuber
Tip out your tuber, compost and all, for a quick once-over.

Start by tipping the Dahlia tuber clusters out of their storage tubs, and have a look for any obviously rotten, shrivelled or split tubers. Remove those, either by very carefully cutting them away with a sharp knife, snipping with secateurs, or gently twisting the affected tuber, which carries less risk of accidentally damaging healthy tubers.

2. Manually Check Every Tuber

March 2018 Dahlia tuber checking
Give every tuber a firm squeeze to check for non-obvious softening, or outright rotting.

It’s important to check every singly tuber in the cluster, in case there’s one that looks fine but is actually rotten beneath its skin. Give every tuber a squeeze to make sure it’s firm and healthy, once again removing any of them that aren’t.

March 2018 rotten Dahlia tuber
If a tuber is rotten you’ll quickly know about it, so don’t squeeze too hard…

You’ll soon find out if a tuber is rotten. Luckily, squishy tubers don’t seem to smell all that bad, but there’s always a risk of squirtage, so don’t squeeze them too hard…

3. Clean Up and Re-Pot

March 2018 Dahlia tuber cleaned up
Remove the rotten or damaged tuber sections and re-pot the remaining plant.

Once you’ve cut, snipped or twisted off any dead or diseased material, you should be left with a clump of healthy tubers, attached to a section of stem. At this point, you can also divide large clusters of tubers. Sometimes they split and separate during the checking and cleaning process. Otherwise, a bit of gently pulling might reveal a faulty line that you can take advantage of.

As long as the section you break off includes one or more storage tubers and a section of the stem / growth node part of the plant, then you should be be able to pot it up and grow on a whole new Dahlia plant from it. We started off with five or six bought-in tubers and over the past couple of years have increased our stock to around two dozen plants.

Re-pot each tuber into a mixture of spent and fresh compost. You can use all-fresh compost, which isn’t a bad idea if you’re planning on keeping the Dahlias in pots year-round, but I’ve found found that if you’re planning on planting them out when all risk of frost has passed then a 50:50 mix of spent – you can re-use the over-wintering compost – and fresh is fine. Once the plants go into the ground they’ll be able to draw on the nutrients in the soil.

Hopefully your efforts will be rewarded with a glorious display of dazzling Dahlias from mid-summer right through to Autumn!

July 2016 Dahlias Top Mix 'Mama' and 'Purple'

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Is it Spring Yet?

Well, what a couple of months we’ve had. After an incredibly mild January, February and March have pulled a double shift on winter weather duty, chucking pretty much the full repertoire of sleet, snow, hail and frost at us, quite frequently all at once. All of which has meant our January plans haven’t moved on as far as we would have liked, but it is what it is: the first thing you learn as a gardener is that you can’t control the weather, you just have to work around it.

That didn’t stop work progressing on Plot #79, our new orchard plot. Orchard-buddy Mike and I covered the plot in heavy duty weed membrane back in December, before planting out 20 trees – stakes, ties and all – in January. We started the job in breezy sunshine and finished it in freezing rain, but we’re now the proud custodians of 11 heritage apples, 4 heritage pears, and one each of quince, greengage, plum, damson and medlar. I’ll write up a more detailed progress report and post that separately.

Plot #79, work very much in progress
Plot #79, work very much in progress

I also found enough dry(ish) weather at the end of January to prep the slab base for our new shed, which we ordered yesterday. It’ll be with us in 3-4 weeks and that will allow us to finally move all the junk out of the greenhouse and use that as proper growing space instead. Cucumbers, y’say? I think so.

Last week was the first reasonably fine, dry spell we’ve had for a while, and I was able to get on with some of those infrastructure and clearance jobs, that I was really hoping to do much earlier in the year, on our main plot #59. Another half dozen recycled concrete slabs laid along the central path, another couple of square metres of the remaining midden mound – a previous tenant’s rubbish dumb, right in the middle of our plot – dug over and a few more kilos of broken glass, metal, pottery, brick, plastic (you name it) picked out and set aside, ready to dump in the annual site skip. Nothing glamorous, but essential work that’s better done than pending.

Another forkful of assorted crap from the midden mound
Another forkful of assorted crap from the midden mound

Jo and I also spent a few hours yesterday planting out onion sets, sprouted shallots and over-wintered broad beans – I know the weather is due to turn a bit colder again this week, but it’s only a short snap, and the plants need to be in the ground rather than the greenhouse – so they’re providing a bit more green amidst the see of brown earth and wood-chip. I noticed that the gooseberry and jostaberry leaf buds are just starting to break, the rhubarb as well, which is always a good sign that things are finally getting underway.

February 2018 - broad beans planted out
After a winter in the greenhouse, these broad beans should be glad to get their roots into some fresh soil.
March 2018 - jostaberry leaf buds breaking
Josteberries and gooseberries are among the earliest fruit leaf buds to show signs of life.

This week’s forecast of a short burst of cold, wet weather aside, I think we can say it nearly, almost feels like Spring is here. At long last.

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