Potatoes ..... to use grow bags or not to use grow bags ?

[kwhitney992000]

In a previous season I planted potatos in rows and was disappointed with the results. Many tubers had damage from various parasites i.e. wireworms , scab, and rodents. I did some research and I thought grow bags and fresh compost would be ideal. I used 15 gallon bags, with 3-4 tubers or sprouts. I planted various combinations of predominately tetraploids purple majesty, purple Vikings, red lasoda, ect I did some pull sprouts and tubers. Long story short I am seeing poor yields AND potato scab. I tried many different techniques so isolating variables is tough at this point. I grew some in a raised bed and they produced huge yield of perfect spuds. Is there any guidelines ? Is it time to ditch the bags? 
Thanks for the wisdom

[billw]

You don't say what climate you have, but that is probably the biggest factor. Growing in bags in a warm climate is probably not a great idea.

It seems that most of the problems that you have can be corrected by soil amendment. Wireworms mostly disappear if you keep the grass at bay. Scab usually means that your soil is not as acidic as potatoes like and/or is deficient in organic matter. Poor yields can be caused by many things, but if the raised beds did well while the bags didn't, I would look to insufficient water as a likely problem. Rodent damage can be reduced by removing cover, filling access holes, and trapping.

[kwhitney992000]

I am in 5 a , davison, Michigan. They didn't seem to get dry. I was ultra sensitive about the water since they were in bags. I believe p.h was an issue. I would have been happy without scab. What is the best way to treat low p.h? Preliminary research has lead me to sulphur? 

[philagardener]

Welcome to the forum, kwhitney992000 ! Either pine needles or peat moss can be used to lower the pH of your soil and add organic material.

It is worth having your soil tested to get a better idea of what is going on. Your local extension agent can provide you with an Michigan State University mailer www.msusoiltest.com/get-your-soil-test/

[robertb]

I'm having much better results growing TPS seedlings in pots which are filled up as they grow than I ever did putting them in the open ground, and they're not being disturbed by foxes or badgers digging for worms. I know pots aren't bags, but I don't have any of the latter.

[Al]

I am lucky to live in an area well suited to growing potatoes; East Lothian, Scotland supplies seed potato to much of Europe. It is pretty much just a matter of digging a trench adding some compost & a handful of fertiliser, then digging them up again a few months later. I often throw grass clippings along the bottom of the trench too as this is said to reduce scab (maybe the fresh clippings alter the pH enough to reduce scab?), the extra organic matter is all to the good, & scab is not a great problem. I usually save some tubers to re-plant unless I suspect some problem with the crop. E.g. Last year the Rooster potatoes had feint brown streaks in the flesh, so they were not re-planted.
  This year is the first time I tried potatoes in containers, mainly just out of curiosity & to see if I can raise an few extra-earlies by starting them in pots which can be protected from late frosts. I got some 50 litre Air-Pot potato towers which I reckoned would take 3 tubers each, my homemade garden compost was mixed with a bit of sieved topsoil & some organic potato fertiliser. The tubers are planted a third of the way up & the pot filled to two thirds, then once the shoots reach the top of the container the plants are earthed-up by filling the final third with more compost. I planted the tubers early April & kept the containers in a workshop until the shoots appeared, then they were moved outside & a bubble wrap cover pulled over at night & left on during cold days. Last frost was mid-May by which time foliage was looking great, plot grown potatoes were only just starting to emerge above ground. The plants actually looked so good that I did not harvest early preferring to let the tubers continue to bulk up. When I did open the containers mid-July there was over 3 kg good sized potatoes from each tower, this is a slightly higher yield per plant than from the plot grown & there were more large tubers. Overall, a success, but with hindsight I should have harvested sooner as the yield was not much different, so the real value of container growing for me is getting an extra early crop. But anyone troubled by pests in the ground or short of space should certainly give it a go, I found the Air-Pot towers to be tough & easy to move (two people required), excellent drainage & super healthy plants, & they should last 10 years or so. I have re-planted with a second crop which might give new potatoes for christmas dinner with a bit of late season protection from early frosts.
Picture of plants taken May 23,  Harvested potatoes pictured July 15

 IMG_1220 by Alex Taylor, on FlickrIMG_1429 by Alex Taylor, on Flickr