I got my first greenhouse last year and my daughter bought me seeds for all the veg she likes. I've planted 'Webbs Wonderful' lettuce and 'Scarlet Globe' radish in pots (both from suttons seeds), and virtually all of them have developed strange looking growths on the stems. Many of the radishes have developed two bulbs as well, and the lettuce are stringy. I've shown a couple of friends who have been growing veg for years and they've never seen it before. I bought good quality compost from a local garden centre as I tried supermarket stuff and it was poor quality.
I've tried to put some pictures on but the system will not accept my files for some reason, so help with that as well would be gratefully received.