Seen at The Festival of the Tree

...if you would be happy all your life, plant a garden ~ Chinese proverb

Tuesday, 27 October 2009

Product Test: Air-Pot Results


Previously
here on Veg Plotting, I've told you about how I got involved in trialling a new method of growing vegetables using an Air-Pot, a rather strange looking planter riddled with holes. I also updated you a while ago on how well things were going and also told you about how I was comparing them alongside using old compost bags.

Today it's time to reveal the final results and the photo shows the total number of potatoes from both trials. From left to right we have Edzel Blue potatoes from the compost bag, followed by the Air-Pot, then Yukon Gold potatoes from the compost bag and finally the same potato variety from the Air-Pot. As you can see the results aren't that spectacular for pot or bag, nor for each potato variety. In terms of weight the pots yielded 575 grammes of potatoes and the compost bags 950 grammes. So the bags have yielded nearly twice as many potatoes in terms of weight, from a slightly smaller number of them.

I've been asked by the company who gave me the pots to trial to rate a number of factors on a scale of 1 to 5, where 1 = terrible, and 5 = good. These are shown below and I've also rated the compost bag method using the same criteria:

Air Pot
Received in good condition = 5
Assembly & initial instructions clear & helpful = 2
Assembly of the pot / bag = 3
Initial filling and planting = 4
Watering/feeding = 4
Rate of growth = 5
Volume and quality of crop = 1
Overall satisfaction = 1
--------------------------------------------------------------
Total Score (% maximum score available) = 25/40 (62.5%)

Compost Bag
Received in good condition = N/A
Assembly & initial instructions clear & helpful = N/A
Assembly of the pot / bag = 5
Initial filling and planting = 5
Watering/feeding = 5
Rate of growth = 5
Volume and quality of crop = 1.5
Overall satisfaction = 1.5
-------------------------------------------------------------
Total score (% maximum score available) = 23/30 (77%)

I've rated the pot lower than the bag in most of the categories because I had to suggest a number of changes to the assembly instructions provided; I managed to assemble the pot incorrectly a couple of times before I got it right (though this was in the space of 10 minutes); I needed to use more compost to fill the pot as instructed; and it required more watering. As you can see the quality of the potatoes is high - both are pest and disease free - it's the woefully small crop volumes that's led to my low ratings.

I don't know yet if my experience is a typical one as I haven't seen any results from the other nine growers taking part in the potato part of the trial. However, the people who chose the tomato/tender crops option do seem to have had a better experience from what I've seen on Gardeners' Click as they've reported earlier and more productive crops.

For me, the only real advantage of the pot for potato production was the reduction of effort in both planting and harvesting. The pot wall could be peeled away easily leaving a rigid pile of compost to dive in to find the potatoes. Therefore minimal lifting or digging was needed, unlike with the compost bag and particularly with growing spuds on my allotment.

I'm wondering if the air pruning of the plant's roots which the Air-Pot promotes might have a detrimental effect on tuber production, especially as my 'spare' solid walled compost bin on the allotment - which was half full of random dumpings of old rabbit bedding + poo, kitchen scraps and large bags of coffee grounds - had a volunteer potato growing in it (probably from the kitchen scraps) which yielded 3kg of potatoes with absolutely no effort at all.

Even if these results had occurred with the Air-Pot (which might have happened if I'd chosen another potato variety or grown them in a sunnier spot), using the same no-cost method of accumulating a growing medium (using peat-free multi-purpose compost would cost around £4-5), I wouldn't be able to recommend them as a viable method for growing your own spuds as the biggest drawback is their cost - currently £35.25 for 2 x 50 litre pots.

From my experience this product is better suited to its existing purpose: the production of healthy container-grown trees. However, I am thinking of adapting my pots - by placing the bottom of the pot higher up the wall - to see how I fare with growing cucumbers next year.

Update: Since writing this, I've now found a couple of people who've posted pictures of their results in the photo gallery on Gardeners' Click. One of them is showing similar looking yields (and reporting higher where artificial fertiliser's been added) compared to his plot grown Desiree spuds.

I've also had a full response to this article from the Air-Pot's manufacturer, including fullsome praise quoted from Terry Walton - see the Comments for full details. Their observation re lateness of planting possibly affecting yield also applies to me as I didn't receive my pots until late May. However, that doesn't cancel out the slightly better results I had via the compost bag method.

12 comments:

  1. Very interesting, excellent report. I grew potatoes in bought potato bags this year for the first time (I have never grown potatoes before) with similar results to your compost bags. Like you I was disappointed with the quantity but the quality was good. I will try again next year as I don't have room to grow potatoes in the gound.

    Best wishes Sylvia

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  2. Sylvia - thanks. You've raised a similar point to what was said at the Food Growing Bloggers meeting on Saturday: that if you don't have space and you still want to grow veg, anything which allows you to do so is welcome. However, this product is expensive compared with other options on the market, or indeed freebie compost bags!

    Simon Platten's talk on his research was also interesting in this respect - economics rates very lowly amongst the reasons why people have an allotment.

    More to come on that one.

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  3. Here's the response I've had from the company who manufacture the Air-Pot over at Gardeners' Click:

    Dear VP,

    Disappointing!

    We too had some mixed results with the potatoes, but know that the yield was down because of the late planting and because the growing media in the Air-Pots was simply not as good as the soil in the adjacent bed. However, the health of the potatoes was better than in the ground and there were no green ones.

    And as you say, the feedback from those growing tender crops has been amazing. We are still eating more aubergines than I ever would have imagined possible, as well as the tomatoes and cucumbers (I don't need to see another cucumber until next year!)

    Terry Walton and many others however, reported bumper results for potatoes too..........I attach his report below:

    "I put an article up about the 'brilliant' crops that these provided. Sorry I should have written to you. I have also recommended these in my articles for the magazines and papers I write for.

    The compost bin is in pride of place in my composting area and works brilliantly. The tall ones were used to grow potatoes and these produced bumper crops. The large diameter half sized ones were used for my cucumbers and produced literaly hundreds of mini cues.

    The big diameter ones together with the very small ones were used in my home garden for growing some super flower displays of petunias and french marigolds as a raised display.

    All in all a resounding success and I would be very happy to do some publicity for these if you require and now that they are emptying they can be stored flat.

    Thank you for allowing me to trial a fabulous product."

    Good luck with your tender crops next year and thanks very much for testing the system so thorougly.

    Best wishes,

    Suzie Single

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  4. In any case, I think you've motivated me to grow potatoes--in some format--next year for sure!

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  5. Monica - that's great! :)

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  6. Interesting, VP. How many seed potatoes did you put in each of your compost bags (I'm assuming you put the same in the compost bags as in the air pots)? You've probably said in one of your previous posts, sorry.

    I grew potatoes in those green canvas planters and I had the same sort of results - quality was excellent; quantity was disappointing. I put 5 seed potatoes in each bag and although I didn't meticulously add up all the amounts, I think we got about 4-5 portions per planter, so about two to two and a half pounds (um ... a bit over a kilo ... OK, just googled for a weight converter and two and a half pounds is 1134 grammes).

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  7. Juliet - I only put one in each bag or pot, simply because this was all I had left to plant when I was contacted about the trial in early May. The instructions suggest 3-4, so this should have made the outcome a little better than the results I achieved.

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  8. Interesting results VP. Many, many moons I go I wrote a dissertion about the use of Airpots in tree production. They have many advantages with this crop, but as pots are designed to prune roots I can only imagine this would hinder the growth of tubers.

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  9. Skinflints like me achieve a similar effect using mypex cut and stapled or tied and filled with compost, which is very similar to the (expensive)patio potato bags. I find that direct contact with the soil gives good results, probably because the soil within the "pot" stays fairly dry, deterring slugs, whilst the roots go deeper, thereby increasing yields. I think research has shown that yields are increased if part of the root system is stressed and another part isn't, although that involved (I think) alternate watering of plants in rows.

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  10. Martyn - I remembered your study and I'm pleased you saw this post. I'm with you on the air pruning not being too good for tuber production, but it does look like others did get some good results. There was plenty of root formation in my pots - the compost didn't collapse when I pulled away the pot walls, but the compost in the bags was all over the place. The potato trial's been more variable than the tender crop one from what I can tell.

    Rhizowen - welcome! Coincidentally we were talking about your blog at the Food bloggers get together on Saturday and I was taking a peak at you earlier! You've got some good stuff there. I was pondering growing some sweet potatoes next year, but I'm reconsidering having seen your results for this year.

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  11. Could the air pruned tubers be affected by soil temperature differences between the pot types?

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  12. Good question anonymous. I'm afraid I don't know the answer. The pots are pretty solid despite the holes, so I don't know whether the soil temperature is actually any different

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