Saturday 24 March 2018

potting

It drizzled for the middle part of the morning, just as I'd finished watering in the greenhouse and the conservatory and got my bucket of hand tools and tub of fish, blood and bone ready to continue mulching the long bed in the front garden.  I hastily put the tools and fertiliser under cover, and occupied myself in the greenhouse with last year's new auricula plants and this year's new dahlia tubers.

The auriculas have started into growth.  They stood outside all year in the shelter of the house, their little pots freezing solid in the cold spells, watered only by snow and rain.  The books and specialist catalogues promise that cold will not kill them.  Their enemy is damp.  Through the coldest months they did nothing, little tufts of wizened leaves in apparent stasis, but in the past couple of weeks they have been on the move, new leaves emerging and expanding.  There are even a few embryonic flower stems.

The year before last's auriculas are in clay pots, but the second batch ended up spending the winter in their deep three inch plastic pots, because due to a communication glitch with the pottery their terracotta pots did not arrive until the autumn when the plants were entering dormancy.  The books and specialist suppliers are united in their advice that you must not pot them on in autumn.  When damp is anathema to them, leaving them to sit through the winter in a wodge of new, unoccupied compost is asking for trouble.

I am using a mixture of John Innes number three cut with a generous proportion of horticultural gravel.  It is a fairly fine, sharp gravel, smaller and sharper than some bags I've bought, and I feel it should do wonders for the drainage of the John Innes.  Two things became apparent as I potted.  The first was that the interior volume of the terracotta pots is not as much larger than the plastic ones as you'd think, because their walls are so thick, although they are almost two inches deeper.  The second was that the amount of root growth the new auriculas had made varied considerably.  Some had thick, strong roots filling the compost in their plastic pots, and will certainly be glad of the extra space.  The others had begun to explore, but not yet fully exploited their existing space, apart from one that had completely failed to root down into the compost below its original root ball.  I didn't risk moving that one into an even bigger pot, and contented myself with giving it a small vintage clay pot in place of the plastic.  Even then its root ball broke up as I was lowering it down into its new container.

I like clay pots for auriculas, partly on aesthetic grounds but also because unglazed terracotta is a breathable material and I feel the extra air and evaporative cooling can only be good for their roots.

I got the dahlia tubers from a specialist nursery whose owner sits on an RHS panel to do with dahlias, and who sounds as though she eats, breathes and lives dahlias, and who promised on her website to send the genuine variety for 'Waltzing Mathilda' and not just some vaguely similar orange-pink substitute.  I am feeling rather grumpy about substitutes after getting the wrong thing from several suppliers in the past couple of years.  Some took my order and then ran out, and others sent things incorrectly labelled that turned out not to be what they said they were.  One of this year's pots of hyacinths, which are supposed to be a dusky shade of violet, includes a rogue pale pink.

The dahlia tubers differ in shape from one variety to another.  'Waltzing Mathilda' has pointed storage lobes that naturally hand downwards like a shuttlecock.  They would fit in deepish one litre pots, but the tubers of 'Gallery Art Deco' were much bigger with globular lobes held stiffly outwards, and needed two litre pots.  I kept to the smallest pot sizes I physically could while fitting the tubers in, to reduce the risk of over watering, as sitting in wet compost can cause the tubers to rot before they manage to grow. 

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