How to Reuse Living Soil After the Harvest (Step by Step)

Can you reuse living soil? Yes – and that is one of the biggest advantages over a classic mineral setup, where the soil usually ends up in the bin after every grow. With Monster Soil you refresh your soil instead of replacing it.

Why you can reuse living soil

Living soil is more than a growing medium: it is an ecosystem of bacteria and fungi that break down organic matter and feed the plant. After a harvest that ecosystem is still there. What has been used up is part of the nutrient reserve – and that is exactly what you top up.

How to refresh Monster Soil – step by step

1. Remove the plant. Cut the stem and take out the bulk of the root ball.
2. Loosen the soil. Break up the used soil so it is crumbly and airy again.
3. Add Concentrate. Mix in 3–4 L of Monster Soil Concentrate for every 10 L of used soil. For a Monster Soil Pot (10.8 L) that is roughly 3–4 L.
4. Moisten. Water the refreshed soil lightly with chlorine-free water so the soil life becomes active.
5. Plant again. Start your next grow as before – sensitive seedlings get a small buffer zone of light seedling soil.

How much Concentrate do you need?

Used soil	Monster Soil Concentrate
11 L (one pot)	about 3.3–4.4 L
33 L (three pots)	about 10–13 L
100 L (nine pots)	about 30–40 L

One 50 L bag of Monster Soil Concentrate refreshes roughly 125–165 L of used soil.

Can you reuse living soil more than once?

Yes. Because you top up the nutrient reserve after every harvest instead of starting from zero, you can reuse living soil grow after grow. Keep an eye on the structure: if the soil gets compact after several cycles, loosen it well before you mix in the Concentrate. Monster Soil Concentrate contains coconut fibre and perlite, which help to keep the mix airy.

What to do with the old roots

You don’t have to sieve out every last root. Take out the main root ball and the larger pieces – they take up space in the pot and take a long time to break down. The fine roots that remain are broken down by the soil life and become part of the soil again.

Tips for reusing living soil between grows

• Don’t let it dry out completely. The soil life needs moisture to stay active, so keep used soil slightly moist.
• Store it cool and covered. If you don’t plant again straight away, keep the soil in a closed pot or container – the lid of the Monster Soil Pot works well.
• Refresh before you plant. Mix in the Concentrate when you are ready for the next grow, then moisten and plant.
• Label your pots. Write the date of the last refresh on the pot, so you always know when it was last topped up.

Do you grow in several pots? Refresh them all at once and keep them covered – then every pot is ready whenever you want to start the next plant.

Why reusing pays off

• Cheaper: you only buy the Concentrate, not a whole new substrate. See what a grow really costs.
• Less waste: no bags of spent soil after every harvest.
• Less to carry: one bag of Concentrate instead of several bags of soil.

Want to see it in practice? Follow test grower Grünblick growing with Monster Soil on YouTube (videos in German).

More real grows: see our Monster Soil grower results.