I have giant wooden planters we built around the edges of our deck last year. We filled them with potting soil and grew some herbs and vegetables. I am wondering if there is anything I need to do to prep the soil (turn it over, add compost soil), or do I put new soil in the planters?
Thank you for writing, and hopefully we can help with your planter questions. Without a photo, we’re not exactly sure how large you mean by ‘giant’, but this sounds like an interesting project. Depending on what you grew last year, and how hungry the plants were, your base soil should be good for this spring’s growing season. The general rules of thumb for herbs and vegetables are to ensure that your planting medium is:
1. Well aerated and not compacted, so do mix with a garden fork to loosen the soil, remove weedy growth, and break up any lumps created by winter frost: plant roots need oxygen;
2. Enriched with organic material, such as composted leaves, manure or garden compost, so perhaps treat your planters with a mixture fortified with micro-nutrients: check with your nursery for a blend that will provide the required nitrogen, phosphorus and potassium: plant roots need food;
3. Well-drained: check your planters for good drainage and structural soundness, but at the same time ensure that enough moisture is being retained by the lined wooden structure;
You may also want to provide some filtered shade for some of your plants, so a movable patio umbrella can also be useful, depending on your deck’s exposure to sun.
Please explore our TMG site, for further info related to your query. For example here is another gardener’s question, similar to yours: http://www.torontomastergardeners.ca/askagardener/container-gardening-on-terrace/
Hope this is some help, and enjoy your new spring garden!