If you have 2' of plant above the ground and you are using both loose, well-drained soil and straw mulch, I think you are in good shape. Potatoes are pretty easy to grow from what I can tell. It's really about timing. Dr. Bob Randall's book about Houston Gardening (the actual name of the book is absurdly long) says it's important that early varieties are selected and started at the right time as you really want to harvest before mid-May when the soil gets very hot and starts to ruin the flavor of the potatoes.
Even though my potatoes went in the ground a few weeks after Dr. Randall's suggested planting date for Houston, I think I am still on track to get some spuds before the heat kicks in. I bet this week of lows in the 40's and highs in the 60's is really good for them. We're finally getting some sun today and will get some sun tomorrow before 2 more drenching days.
C'mon guys (or gals), more flowers!!
