Right the first time, 6.5 to 7. Soil will gradually drop in ph the longer it is used and this can have all kinds of nasty effects. The best way I found to counteract this was to add 2 tbls of garden lime (dolomite lime) per gallon of soil. It will not take your ph above 7 and will stabilize ph levels for the long term. This can be especially important for heavy fertilizing, which can be very acidic.