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The Goop on Radishes

Can you really have a better harvest if you add beneficial, living and active microbes such as contained in Goop to a commercial seed compost?


If you can’t wait, here it is: The results in increased yields when comparing like for like, were not just detectable but also consistent and huge: 55% heavier radishes on average! Read on for more details.

What the heck is the ‘Goop’?

Glad you asked.

The Goop is a highly concentrated compost extract made by soil biology and composting experts at the Soil Ecology Lab in Hampshire. The extract allows you to add not just diversity but also high numbers of beneficial microbes like protozoa, nematodes and fungi.

Micro fungi especially, which need time, the right food, environment and very low to no disturbance to grow their filaments and webs, are usually missing or very low not just in backyard compost piles and garden soils but, sadly, also in all commercially available composts.

What do these microbes do?

They create a living web of interconnections in the soil. One of the effects is that nutrients become available for plants in an on-demand, just-in-time fashion and in greater diversity than any chemical fertilizer could ever provide resulting in healthier roots and plants.

So far, so good. But does it really work?

Preparing the planters

I prepared two identical, round 25ltr planters (40cm in diameter, 20cm in height) by filling both with the same Sutton Seed compost. I diluted 10ml of Goop in 1ltr of rain water and mixed this well into the 25ltr compost of the ‘Goop planter’ and added 1ltr of rain water to the compost of the other planter.

This is a very low application rate as you would when applying this on an agricultural field. I wanted to see if adding so very few microbes would really have an effect.

5 rows of 5 French Breakfast 3’ radish seeds were sown into each planter with each row arranged like spokes running from the middle to the edge. Sown on 8 April.

In the sections in between these rows I sowed herbs like parsley, chives, coriander etc making sure I sowed everything in exactly the same pattern with exactly the same number of seeds to have the same growing conditions in both planters.


When it was time to harvest, I pulled up all 5 radishes of one row and compared the weight of the radishes that had grown in between the same herbs in both planters. So, I would compare the 5 radishes that were grown in between the chives and parsley in the Goop planter with the same positioned radishes in the compost only planter to make it as much of a like for like comparison as possible.

My Observations

Above ground, plants still in soil:

The plants did not look different. I asked a couple of friends and they couldn’t really tell the difference either. 

Biomass/ weight of the whole plants when harvested after 6 and 7 weeks: 

The Goop plants had 22% more total biomass (whole plants including roots and leaves.) when comparing one row with its counterpart in the other planter.

Biomass ratio leaves vs roots:

What surprised me was the different ratio of the roots/leaves biomass in both planters and this is where the Goop radishes outperformed beyond my expectations. 

On average, the total weight of the roots i.e. the radishes themselves grown with Goop was 55% higher than the radishes grown in compost only. 

Even if there was a ‘dud seed’ that for whatever reason didn’t grow very well, be it because it was a bad seed or because it didn’t get enough light or nutrients due to a strong plant next to them, the sum of the weight of the radishes of that Goop row was still higher than the equivalent row in the compost only planter. (see pictures and table below)

There was a higher variation in size within the Goop rows vs the ones without.

Taste comparison:

There were no woody radishes in either group. As for taste and texture I didn’t noticed a difference between the Goop and the compost only radishes.

In pictures:

Across all 5 rows, the total weight of all 5 radishes grown with Goop was bigger than their goop deprived counter parts even though there was usually a radish that didn’t grow too well because of lack of space and light. The other 4 made up for it. Which means, if the growing space was optimised for spacing and light the difference would very likely be even bigger.

Whole plants, top rows are grown with Goop, plants are placed in the position they were in the rows

The Goop on Radishes – Data

Review Date
Reviewed Item
The Goop - Beneficial Microbes in Bottle
Author Rating
Product Name
The Goop

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