All about mulching
In the summer of 2003 when the weather was exceptionally hot and dry I had
problems with some of my thymes drying out and a couple of plants died.
Drastic action was required to prevent more losses.
When one has a gravel mulch the usual amount to use is about half an inch (12 mm) of gravel.
I therefore decided to increase this mulch to virtually 2 inches (50 mm), basically gravel bed conditions.
This has been even more successful than originally envisaged.
The thick layer of gravel not only stops the soil from drying out and therefore prevents the thymes from dying,
but there is also an added bonus.
During the winter of 2003-4 I found that all the thymes were much healthier
with less die-back and they started their spring regrowth more quickly.
They also grew very well in the summer of 2004 when there was a lot of rain, which just drained straight
through the gravel to the roots rather than sit around on the surface.
Normally when thymes drop their dead leaves on to the ground they just lie there looking untidy.
However with this deep gravel mulch they can very easily be brushed straight into the gravel
where they will eventually break down into compost as happens with thymes in the wild.
My advice is that a deep gravel mulch is the preferred way of growing thymes,
both to prevent their drying out in a dry hot summer and to prevent excess water remaining around their necks in winter.
I now feel that with this gravel bed regime it should be possible to grow thyme in clay soils,
with the addition of extra gravel dug into the soil, unless of course the ground is so water
logged in winter that it is practically swamp conditions!
As far as suitable mulching material is concerned, I use pea gravel in a pleasant mix of colours.
Personal taste and local availability should be the guiding factor in choice.
For example, in a limestone area limestone chippings would be eminently suitable, or slate chippings where slate is the local rock.
All about propagation
Thyme growing in the wild is accustomed to rooting into the surface mulch made up of composted leaves
on the soil or rock where the plants grow.
This is also the type of soil into which generally the seeds are scattered and in which they germinate.
For optimum results, seeds and cuttings should be started in a non-soil type of compost,
which replicates the type of soil they are used to in the wild.
Personally I use a commercial non-peat compost, made up primarily of composted bark.
I find this very satisfactory and in fact it gives better results than the peat based compost I used to use.
Seed
Seed should be sown either in a seed tray, or a large tray made up of separate modules.
The seed should be sown directly onto the surface of the compost and does not need to be covered.
The trays can be covered with a propagator lid to prevent drying out,
placed on wet capillary matting and protected from full sun.
Do not water from above. Once the seed has germinated the cover should be removed.
Recently a method to keep the stems of seedlings short and prevent them from bolting has been discovered.
Each day gently brush one's outstretched hand across the seedlings.
This has been found to produce strong, shorter stemmed plants.
Once the seedlings are large enough they can be potted on into 60 mm square pots using the same non-soil compost.
It is wise to top dress the soil with a thin layer of gravel to prevent the soil from drying out.
Once the plants have a good root system, filling the compost in the pots,
they can be planted out in their final positions in full sun and with a 50 mm deep gravel mulch, or in terracotta pots.
Cuttings
The best time to take cuttings is mid to late summer following flowering.
With cuttings taken in early summer, there is the risk that they will flower
before the roots are sufficiently developed to support flowers.
However, following flowering, thyme puts on a lot of new growth.
It is therefore an ideal time to take cuttings when pruning the dead flower stems.
In creeping thyme, tiny roots often develop from the leaf nodes and these are ideal.
Young, but not too soft plant material gives best results.
Ideally cuttings should be 50-60 mm long, avoiding any stems with flower buds, either a single stem or 3 or 4 stems,
depending on the size of the parent plant and personal preference.
With bushy thymes, firm stems should be used, soft stems are liable to rot before rooting
takes place and woody stems are unlikely to produce roots.
It is advisable to remove the lower leaves from bushy cuttings, but it is not necessary with creeping thyme.
They should be rooted in the same non-soil compost as for seed sowing.
I prefer to use trays made up of separate modules for taking cuttings.
Simply fill the modules and then use a small dibber to insert the cuttings. There is no need to use rooting hormone.
Place the trays on wet capillary matting and cover with a sheet of woven shading material and keep out of full sun.
It is not necessary to use a propagator lid and after a few days the shading material can be removed.
Once the cuttings are well rooted, they can be potted on into 60 mm square pots of the same
non-soil compost and covered with a thin layer of fine grit. Once a good root system has been formed,
they can be planted out into their final positions in the soil and mulched in the same way as the seed raised plants.
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