It often happens that too much potting soil is bought at the beginning of the planting season, which is then left until the following year. Can this soil still be used? The question also arises with old soil from flower boxes or tubs.
Unopened potting soil usually has a very long shelf life
Potting soil in sacks
Potting soil that is packaged and stored in a cool and dry place still contains its nutrients after a year and can be used without any problems.
However, if the plastic bag has already been opened or even just torn open and is also lying outside, the nutrients have been reduced or have been used up. But this earth does not have to be thrown away. It can be enriched as potting soil with slow-release fertilizer or worked into the garden soil as mulch material.
An open sack of potting soil dries out if stored incorrectly. It is therefore not advisable to use it in pots or flower boxes (€16.99) unless the soil is mixed with garden soil. Dry potting soil can also be incorporated into normal garden soil. Here the earth is gradually getting wet again.
Old earth from flower boxes
The old soil from flower boxes or tubs is often completely rooted and should be disposed of. Break up these clumps of roots and add them to the compost.
If the potting soil is not rooted, it can be worked into the garden soil. It is no longer suitable as a basis for new planting. On the one hand there is a lack of fertilizer and nutrients and on the other hand the soil is no longer stable. It would no longer support the plants and would collapse when it rained.
Store potting soil properly
If potting soil is left over when filling balcony boxes (€109.00) and tubs, it can be stored and used later. However, correct storage is crucial here:
- an open sack of potting soil should not be left outside
- the rain flushes the nutrients from the soil
- humidity changes the acidity of the soil
- Weed seed invades
- unwanted seedlings consume the nutrients
- Pests seek shelter there
Properly stored, i.e. closed, cool and dry, potting soil can be kept for about twelve months. After that, it loses nutrients, but is still optimal for weak consumers (plants with low nutrient requirements). For heavy or medium feeders (plants with a heavy or moderate need), the potting soil should be improved with compost or a slow-release fertilizer before use.