I AM full of shame and haunted by an overwhelming sense of guilt. I don't know how I'm ever going to look anybody in the eye ever again. I have done something this weekend that I always swore that I would never do.

In my defence, I can claim it was completely out of character, but I suppose some would say that it was only a matter of time before I started experimenting with it. I had watched others doing it and I had started trying to try and justify it in my mind. There is no easy way of saying this, but I have put decking in my garden.

This is how it happened. I recently moved from a classic Georgian town terrace house with the usual moderate garden (hedge all the way round, lawn and a few dry borders), to a small country cottage with a virtually untouched patch of grass the size of half a football field behind it. At the bottom of the garden is a small orchard (five apple trees, one pear and one Victoria plum tree).

I thought that it would be quite romantic to let the grass go wild under the trees and turn it into a small flower meadow (with the hammock swaying gently above it). The idea had to be modified though as I suffer quite severely from summer hay fever. I am allergic to grass (hairs, pollen, sap, the lot) and conifers.

The modern trend for meadows is to do away the common grass and plant it up with ornamental grasses interspersed with things like iris, red-hot pokers and hardy geraniums. This is called prairie planting. The essential ingredient for prairie planting is the tall, willowy stemmed, purple-topped Verbena bonariensis. Bulbs are added (I haven't done that bit yet) to provide colour throughout the year. The whole reasoning behind it is that it looks after itself. It needs minimal maintenance, just a bit of an end of winter clip. It changes form and pattern each year as conditions favour one plant over another. It self seeds, adding to the surprise and unpredictability.

Anyway, there is just enough room between the orchard and the small summerhouse in the corner of the garden to have a sitting out area. I had envisaged the floor surface to be of some sort of paving. However, after sitting down and day-dreaming in that corner of the garden one mild evening, I came to realise that the harshness of stone paving just wouldn't fit in with the softness of the prairie planting. I needed something warm, welcoming and comfortable, not hard and cold. The only solution was to use wood. So decking it was.

I went for a thick, chunky style, not the pretty, delicate and more expensive tailor-made ridged planking. I used scaffolding wood, a good two inches deep and six inches wide. The only difficulty was getting the stuff home in the car. Next time I will pay the extra for delivery.

I decided to make the deck come out from the summerhouse in an arching curve, to complement the sweeping swathe of prairie planting under the apple trees. This would soften the design even more.

I levelled the land and placed my support struts at 90 degrees to the summer-house. Then I laid a membrane (like plastic or polythene with tiny holes in it) over the struts and the ground. This would prevent weeds growing up from beneath the structure.

The main decking planks were then cut to size and screwed on to the support struts. It only took one weekend to build, and it wasn't too physical or mind blowing. The only secret to joinery in the garden is to make sure that you have the correct equipment and have the courage to make the first cut. Forget Charlie, I'm going for Tommy's job next!

JOBS TO DO THIS WEEK

Thin out seedlings

Seeds that have been sown straight into the ground outside, or into trays in the greenhouse, need to be thinned out now. It takes courage to pull out healthy plants but those that are left will benefit from it. Start now, taking out every other plant, or any that appear to be weaker. Each week, repeat the process until you have created enough space for each plant to grow. The bigger the space, the larger the plant.

Plant up your hanging baskets

You can finally get those baskets out of the garage or from under the greenhouse shelving and start planting them up. If you haven't been potting on small seedlings bought earlier in the year then get down to the garden centres and choose a handful of plants for each basket. Try and combine taller plants such as geraniums and fuschias with spreading ones such as petunias. Mix big flowers like begonias with smaller frothy ones like lobelia. Be daring and experiment with colour schemes.

Plant up dahlias

Dahlia tubers which have been over wintering in a frost free greenhouse can now be planted up in tubs, pots and borders. Use a good peat free compost and plant the tubers four to six inches deep, and two to three feet apart. Make sure that you water them well in.

Tend to the strawberry patch

Hoe and weed the soil in between each strawberry plant. Cut off any runners and plant up any off shoots, either back in the bed or in pots. Cover the ground around and under each plant with a good layer of straw.