Soil Beneth Grass....

Hi, is this going to be a screen of sweet peas across your lawn? If yes, then you will need to be particularly vigilant at keeping the grass from encroaching the sweet pea plants once the grass begins to grow strongly which for us is Mid May, but for you it will probably be earlier, After this prolific grass growth that ususally lasts for a couple of weeks then a weekly trim should be enough. If we get a 2006 summer where there was no rain for weeks then you will need to water the little chap regularly as grass is very efficient at removing any free soil water..much more efficient than Mr Sweet Pea..unfortunately. Make sure you give him a good drenching a couple of times a week as this is more beneficial than a more frequent wetting of just the surface. Having said all that your plan sounds great and I await a pic of your first blooms.