Problem - Decreasing soil fertility

In 2017 after moving into a new home I created two garden designs where I transformed both the front and back gardens from a non-productive lawn into productive gardens growing a selection of produce.

The front garden design has a more traditional kitchen garden layout growing mostly annuals in beds using no-dig growing methods. The back garden has a food forest garden design focusing on perennials. Both gardens are of small size using intense growing methods stacking as many plants as possible into the small areas.

When constructing the designs, the soil was a heavy clay with a large amount of stone, the front garden once dug down sits on what amounts to builder’s rouble, the back sits on a rock ledge varying in soil depth from around 300mm – 1 meter.

After a few growing seasons, soil fertility has noticeably decreased. In the first season, the plants grew extremely well, by the third season this vigour has started to wane reducing their yield.  

Since the formation of the gardens, I’ve added various soil amendments that have been brought in from off-site. The back garden was mulched around the fruit bushes with farmyard manure, along with a mulch of wood bark chipping over the whole garden in the first year.

The beds in the front garden were mulched with compost brought in from an allotment I had at the time.

When I moved into the property I brought with me a worm composting system, and I set up a compost heap for kitchen waste. The compost heap has grown as the garden has progressed to also composting hedge cuttings and garden waste.

The problem is decreasing soil fertility, I would like to aim at improving the current composting methods, look for ways to add more value to the existing soil creating a soil microbiome that is conducive to sustaining a productive garden.

Using permaculture methods, I would like to limit the need to bring external resources into the garden trying to create a closed-loop fertility system.  

Here are the links to both Garden designs.

Front garden - Kitchen Garden Design

Back garden - Foraging Garden Design

The front garden before and after

The photographs below show how much change the front garden has gone through between 2017 and 2021. Growing mostly annuals requires highly fertile soils, there is a greater need in this type of garden to keep adding soil amendments to the soil to keep the fertility high.

The back garden before and after

The photographs below also show how much change the back garden has gone through between 2017 and 2021. With using the forest garden design, once fully established this garden will not need as many soil amendments as the front garden but it still needs attention as to how to keep the soil healthy providing all the nutrients that the plants need.