Friday 20 May 2016

Hard and Soft Growth

The soft new leaves are normally damaged by frost and dry wind
My post is a bit of a ramble today with few actual facts, some speculation and more questions than answers. I cannot actually tell you what hard growth really is in plant physiological terms but it seems to be a phenomenon that most gardeners recognise. I don’t know whether it is a bad thing or a good one!
I was first introduced to the concept by Alec Fox, my old garden foreman when I joined Hartlepool’s Brinkburn nursery to gain my precollege experience. He was an old fashioned son of the soil and from a long tradition of private service and gardening methods going back to Victorian times. I would like to add that the Victorians were better gardeners than we are although their techniques were geared to more primitive technologies and lack of modern materials.
The new fangled peat based composts had just appeared on the scene. In contrast to the established John Innes soil based composts which in those days a gardener would firmly tamp down (yuk) in a pot or a tray, peat composts were used at a ‘natural density’ where compost was allowed to settle with no more than a tap or a shake. The plants in the looser un-firmed peat compost grew more quickly and softer. No doubt nutrients were more readily absorbed and arguably the plants were more luxuriant and healthy.
According to Alec they were less sturdy and more prone to pest and disease.

I was tempted to buy two soft tunnel-grown aubretia on the market this Spring. It was immediately potted into a larger pot and given a week  in my unheated greenhouse - next to the open door

Now going over it has given us six week of colour outside our conservatory. Had I put the new soft plant outside immediately it would be dead!
Bedding plants
I think gardeners these days gardeners are familiar with soft growth when they buy their Summer bedding plants from a garden centre. The old fashioned concept of ‘hardening off’ seems to have been thrown out of the window! Plants propagated in warm humid tunnels don’t have the toughness to go straight out into the cold! Sudden low temperature and worse, in my opinion, cold drying wind severely check growth or even kill. 
A gardener’s solution to modern professional omission is to try and harden the tender plants themselves. Apart from not buying and planting too early there are several alternative actions a gardener can take.
  1. Retaining the plant in its container for several days and placing outside in a protected position perhaps by a warm wall. If wind or frost is forecast place the plants inside a garage or shed for the night.
  2. In complete contrast if there does happen to be a brief opportunity in a short mild spell get the plants straight into the ground. If your calculations go awry cover them with newspaper, plastic or fleece.
  3. If you have an unheated glasshouse or cold frame use it and its ventilators to gradually  acclimatise your new plants. Even so on a very cold night throw some cover over them!
  4. Be aware that slugs and snails love soft distressed plants.
  5. The amateur gardening press excessively simplifies and lumps together bedding plants  when it advises gardeners when to carry out their planting. Such as sweet peas and antirrhinums can safely be planted in the garden more than two months earlier than begonias. Provided they are well hardened.
Nursery practices
When I have young woody plants I have raised from seeds or cuttings they grow very slowly. It can take years to reach an acceptable size for planting. If my living depended on them I would starve. Growers have learned how to make their plants grow faster. Sometimes this is by highly skilled and subtle ways working with nature and learning an understanding of plant physiology.
More often they achieve quick results by providing protection from cold and wind, using artificial heat wisely and generous feeding. Plants will often respond hugely to extra nutrition providing it is very well timed. 
When I was a young teacher the research stations talked about achieving maximal optimum growth. No longer a fashionable term - it is too honest - it’s what good successful growers do. Their use of plastic tunnels has provided a revolution in production. Hardy plants are grown inside for all or most of the year. Plants will sometimes come out of a micro-propagation laboratory and be rapidly grown on.

By any definition these plants are soft! Indeed as a result of soft and forcing growing conditions where pest and disease thrive some growers use pesticides in a preventative way. I am grateful for this when these days I am less likely to be buying in whitefly and red spider mite. 
I am less impressed when the prophylactic systemic fungicide runs out and my newly purchased Dicentra ‘Luxuriant’ dies yet again! In contrast I am delighted when a returnee garden visitor who bought one of my own plants that I had more or less chucked into a pot reports that it is really thriving in her garden.

golden bleeding heart
Dicentra spectabilis new growth is very soft and is susceptible to dry wind and sharp frost.  

My coincidence I read today in ‘The Hardy Plant’  wonderful nurseryman Bob Brown advising his readers to buy Trachycarpus fortunei, the Chusan palm that had been grown ‘hard’ and was not displaying stretched long internodes. I thought he was a bit hard describing some plants as etiolated Italian imports! 
What about the Dutch? When I see large lanky Daphne mezereum at the garden centre I shudder.

It might take me five years to achieve a large plant  - but it won’t be soft!
Mike’s tale
I asked botanist friend Mike Ashford whether the terms ‘hard’ and ‘soft’ meant anything to him. He immediately told me a story. It does not necessarily draw a morale that I might wish to pursue but I will repeat it anyway!
We grew half an acre of commercial tomatoes variety Minicraigella at our horticultural college. Our holy grail was to achieve a yield of  a hundred tons per acre. We always failed. Today two hundred tons is routine in the trade. (Perhaps our efforts were not helped once when  a student de-leafing removed a whole row of flower trusses!)
Even with a variety with tasty Ailsa Craig genes our tomatoes were round, red, uniform and pappy. Just like modern ones. Not a surprise when the sugars, acids, nutrients and vitamins have to go so far round.
Our foreman David Coe would sell surplus tomato plants to his friend who had his own small holding. His mate was not a good grower. His watering and feeding were somewhat erratic and his unsterilised soil was riddled with pest and disease. His tomato plants were ‘hard’ and low yielding. They were absolutely delicious!

Tomatoes can be grown a little harder by being a little more sparing with the copious water that they need. When the sweeter cherry tomatoes were introduced to the market growers were advised to use a ‘drier regime’ . This had some success and they started to build a reputation.
Unfortunately high yield was a sweeter cherry for some growers....

My own tomatoes are delicious. You might draw your own conclusions....

My sugar snap peas grow softer in the greenhouse but they are sweet, disease free and early. That's not to mention the pretty cut edges eaten by the pea weevil!
I will be blogging about my charcoal composts at the end of the summer. My tomato growth is healthy but perhaps a little harder than usual

Home grown tomatoes always taste good
Still in the realm of vague and perhaps disconnected science, scientist friend Peter Williams reminded me of the imprecise notion of ‘ripening wood’. Woody plant growth undergoes transition from soft young shoots to hardwood at the end of the season as lignification proceeds. 
Tongue in cheek he declared he could not tell the difference between soft cuttings, semi ripe cuttings and hardwood ones. The serious point he was makings is that amateurs worry too much about definitions and precision. For him although his methods of taking and management of cuttings will vary with season it is merely a seamless progression!

If you want to read further about how I grow tomatoes, my interest in charcoal or my dicentras use the links in the right hand column. If you want to enjoy the excellent magazine 'The Hardy Plant' written by real gardeners rather than journalists you can join the Hardy Plant Society here.


  1. Naturally fledgling amateur gardeners are drawn down the path of varying and often contradictory advice from the media because it is difficult to quantify practices learned from years of experience. One can only hope that that plants grown in poly tunnels in Holland can withstand the rigours of actually being exposed to our winter conditions, in fact I have never had a garden centre bought (not by me, may I add) perennial survive the winter in my main border incredible as it may seem.
    As you have pointed out Roger,commercially grown plants are subject to artificial conditions particularly those produced by micro-propagation which are probably the most vulnerable.
    As far as soft wood, semi-hardwood and hardwood cuttings are concerned it is definitely very "old school" but again led by the media drawing amateur gardeners who are keen to learn into principles which date back to Victorian times almost as if there is an element of liability, however an experienced gardener knows what to propagate from.
    This is the thing which really bugs me, how do we encourage people to be interested in gardening and make them experienced gardeners when the industry is totally indiscriminate in what it sells to the public.
    Do we give up and realise that it is actually a skill which used to be passed on through the generations but like cooking has become a TV spectator sport?

    1. Thank you Rick - I thought this might be a subject close to your heart. Your wisdom is appreciated.
      We gardeners are such tolerant folk and tend to blame our own incompetence when a garden centre plant dies

    2. Sorry about the bit of a rant Roger, bad day! I should have said that perennials from the garden center which are planted in later summer and early autumn do not survive.

  2. Garden club and NGS plant sales are a good source of 'hardy' plants as are small local nurseries.
    Our outdoor neglected tomatoes always taste lovely and sweet.

    1. I have currently four healthy young dahlias and three honesty grown in my unheated greenhouse from the seed supplied by you two months ago Brian. I meant to mail you my thanks but have lost your address! Perhaps you might drop me a reminder.
      The plants are hard and sturdy and I have today planted the honesty to catch the rain!

  3. The information on the tomatoes was new to me. I did not realize that holding back water would produce a "hard" and sweeter tomato. It makes good sense though. I do know what too much water does, but providing a bit less sounds like a good plan. Growers have to be smart now a days because there is a lot of competition and weather many times affects profits. Our area really does have quick results by excessive feeding. Our growing season is short, so plants need to shoot up quickly to bloom.

    1. Yes heavy feeding with lots of water contribute to heavy yield for commercial growers.
      I don't think we amateurs need to consciously reduce water, many new gardeners in fact do not water them enough!
      There are so many factors in our home growing of tomatoes that effect taste!
      Anyone putting on tomatoes in my search box will find my piece about tasty tomatoes


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