Friday, 1 August 2014

From Could Do Better to Couldn't be Worse

That about sums up our experiment of growing potatoes under weed control fabric. Our experiment started back on 10 April when we planted two rows each of first early potatoes Casablanca and Rocket with a row of each planted conventionally and under weed control fabric.
This is how the ones under the fabric looked before I began to lift the potatoes. All four rows had been affected by blight early in June but the ones under the weed control fabric less so than the ones planted conventionally. I didn't know what to expect when the straw and fabric were removed.
With the fabric removed from the row of Casablanca it was a bit odd to see potatoes on the surface of the soil but as I looked a bit closer my heart sank as I saw the slug damage to virtually every one of these potatoes. This was probably my worst fears of using the fabric in that it would provide a safe haven for slugs with no obvious predators.
I started putting the slug damaged potatoes in one bucket and any undamaged ones in another. As I collected the potatoes on the surface the undamaged bucket remained worryingly empty. It was then time to see if there was any crop underground. Fortunately as I dug up each root I found a decent crop of undamaged potatoes under each one and thankfully at this stage the undamaged bucket was filling up faster than the damaged one. By the time the whole row was lifted I had 9.97kg of quality potatoes and 3.90kg of slug damaged ones ready for the Council recycling bin.
It was then time to lift the weed control fabric from the row of Rocket potatoes. I'm not going into great detail but this was one of the worst crops of potatoes I can remember lifting. After a couple of roots I would have left the whole lot in the ground if that were an option. Almost 100% of the crop was damaged in one way or another with either slug damage or what I'm assuming is wireworm damage. It might be possible to salvage some usable potatoes from the wireworm damaged ones which amounted to 6.3kg but the remaining 5.73kg are only fit for throwing away. Some of the tubers were badly affected by blight giving off that unmistakable smell as the potatoes had already turned to mush.
They don't make a very pretty sight do they. 

So what can I make of our experiment. In out and out crop weight the potatoes under weed control fabric produced heavier crops but in the case of Rocket with unacceptable amounts of slug and wireworm damage. Casablanca on the other hand isn't quite so straightforward. There was far more slug damage under the fabric but the crop of undamaged potatoes was 9.97kg under the fabric compared with 5.29kg grown conventionally.

My own conclusions are that I’d probably give using fabric another go. I wouldn't use the method for first earlies as it’s not that easy to just dig up one root and leave the rest growing. Having a look under the fabric to see how things are progressing  seems a good thing but isn't that easy to do in practice.

I won't be growing Rocket again. The row planted conventionally suffered pretty badly from slug damage too when a row of Nicola planted alongside didn't have any slug damage at all. I’m sure some varieties of potato are more susceptible to slug damage than others and I've now put Rocket into the very susceptible category.

The fabric and straw have been put back over the bed and will be left there until the autumn when it will be dug over for winter. The soil wasn't quite so dry and hard as that where the conventional planting had taken place but it would certainly take a lot of work to get it ready for another crop straight away.
I’m not sure I want to lift any more potatoes for a while. Lifting a row which might as well be dumped straight into the Council recycling bin is a bit soul destroying. 


  1. Disappointing results, the slugs have had a good time. At least you know to avoid Rocket now. I hope you have enough good potatoes to last you a long time.

    1. Still some more potatoes to lift. I'm hopeful of enough to get us through winter at least.

  2. What a disappointment. I think you should just put it down to experience, at least you've given it a go, you now know the results of your experiment and you can go from there next year when you're decided how to grow your potatoes. It's just a shame that blight's hit as you'd have had better results had it not.

    1. I suppose when they got blight in June I wasn't expecting any crop at all from these potatoes.

  3. I always wondered about weed control fabric and the slug issue. I don't think it would work too well for me as I've a huge population of slugs & snails and I think they would set up home under the fabric. Glad to hear you potato harvest turned out satisfactory afterall.

    1. I'm still not sure about the slug problem with weed control fabric. We've grown our carrots under it for the last couple of years and haven't noticed any increase in slug damage to our carrots.


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