Raised Planter Bed Soil
I have a large planter box that has no soil, but only bags of mix/mulch. What specific nutrients do I need to add to the mix/mulch to keep it at its best? My vegetables didn't have a good crop this summer.
In general, it is advisable to empty, clean thoroughly (if it’s not too large), and ensure drainage holes are adequate before filling your planter box with new container mix in early spring. This is because plants growing in containers and raised beds do not have access to the same amount of soil nutrients that plants growing in your garden do. Replace old soil with fresh container mix and apply side dressings of fertiliser throughout the growing period. Try Daltons Garden Time Vegetable Mix or Daltons Garden Time Planting Mix. Alternatively, you can purchase Daltons Premium Garden Mix in bulk from your local Bunnings store.
Container mixes have been developed specifically for growing vegetables and flowers in containers. It allows for free drainage while retaining sufficient nutrients for the development of healthy veggies. It also takes the guess factor out of developing your own growing medium where it can often be quite difficult to discern what nutrients are available in your soil and in what amount.
If you are eager to begin the process, you can certainly empty the planter box and clean it very thoroughly anytime during the winter. If you wish to grow summer salad vegetables however, it would be better to leave planting until at least late September or early October. It is also worthwhile adding a layer of mulch on top to protect the soil and keep moisture from evaporating.