Gardening Notes Taking a leaf out of good practice

Jim McColl

In our last Beechgrove programme, broadcast in early October, we discussed the options on whether or not to cut down herbaceous plants at this time as part of the general autumn tidy-up and secondly whether or not to apply a mulch to the borders in late autumn.

It was Carole and I who talked about the tidy-up and rather predictably, I suppose, my choice was to clean up and at home, we are still at it.

The basis of my conviction is not just a Calvinistic attitude to tidiness, it is based on the fact that dead foliage and other detritus isn’t very attractive to look at and though it does shelter beneficial beasties, the nasties benefit too.

To add tomy argument, I would suggest that in any well-stocked garden with a diversityof plants, there are still plenty safe hiding places in a clean and tidy layout.

Carole did make an excellent point that some garden plants, in particular the grasses, look delightful in their gracefulness, even in winter. Agreed, wholeheartedly.

This line of thought came to mind as the HG and I were gathering leaves from the lawn and surrounding borders. The other topic on that Beechgrove programme tackled by George and Chris was mulching.

Should borders be mulched at this time of year? In the natural world, these deciduous leaves fall to the ground and stay put, so to speak.

They act as a very useful mulch and are part of the essential natural, annual re-cycling system, eventually rotting down to be incorporated in the soil.

In the garden, they perform the same function on bare ground in between plants. Additionally, they provide an insulation layer for the root system of plants that may be slightly tender.

As it happens, in all the years and in all the places I have worked, autumn mulching has not been part of the tradition. I have never stopped to ask the reason why until in recent times, I have become aware that some gardeners swear by the technique.

Our leaves, as I said before are collected in a heap, allowed to rot down and then returned to the soil, being forked in as a topdressing.

When we moved into our downsized plot, much of the garden area was filled with trees and shrubs– that was five years ago and at that time, the areas were immediately covered in a top- dressing of finely chopped bark as a weed suppressant thus reducing the workload but that protection has now gone.

In the meantime however, the trees and shrubs have thrived and in places there is now excellent ground cover.

You may remember that some months back, I did a “plant of the week” featuring the most successful ground cover specimens where there is no need for mulching now. What should we do with “old” potting compost? Re-cycle it, of course.

As you know, I grow my tomato plants in pots, in an Autopot automatic watering system. At the end of the season, having shut off the automatic watering system, I cut off the top growth and lifted the pots clear of the watering trays, to allow the compost medium to dry out.

The next job is to recover as much of the growing medium as possible, using a hand fork. The accumulated “used” compost will be stored until late winter and then reused to fill baskets and tubs, mixed 50:50 with fresh new compost, as we make ready the 2016 summer displays. The only other ingredient will be slow release fertiliser.

Solution to a problem

During the above process, I found the answer to why my Shirley tomato crop was disappointing.

The two Shirley plants were in the watering tray next to the reservoir and I have discovered that they were getting more water than the other plants in the next two trays.

I have never had this happen before and how did I find out? Firstly, the compost in the two Shirley pots was still quite wet when I came to tip them out whereas the compost inthe other pots was quite dry as I had expected.

The second bit of proof relates to the size of the root system. It is a very arbitrary measurement but just look at the size of the recovered root mass in my picture. On the left the root mass of a Shirley plant and on the right the roots on new favourite Rosella.

In retrospect, I can only assume that the little float switch on that first tray was faulty – it will have to be replaced for next season.

The difference in the size of root systems. One the left Shirley and on the right Rosella

The stripped out watering system, showing reservoir in the background and the location of that faulty blue coloured float-switch

That recovered compost to be re-cycled

A reminder of one of the very successful ground cover plants. Cotoneaster dammeri ‘Oakwood’. One plant covering about 4 square metres