Many gardens today are newly created, often this means that the topsoil, turf, shrubs and trees etc have all been brought in and an almost instant garden created, even if this is not the case and the garden has been created from an already existing but neglected plot then this will have usually involved a great deal of mechanical work and suffered through the use of chemicals whether its sprays or so called “composts”.
Worms do not like disturbance, therefore if the soil has been imported or mechanically dug and moved on site many of the worms will have moved or been killed off, the end result being a nice looking garden (but unhealthy) and no worms!
Do we need worms, are they that important?
The answer is undoubtedly a resounding yes. Worms create the very soil that the plants live in, they do this by digesting all the organic matter left on the surface through dead plants, leaves etc (without them doing this the planet would now be miles deep in decaying vegetation!). As this matter is digested it is then deposited back as “casts” (actually worm poo!) this, when added to the ground up rocks and stones gives us soil.
This soil when it has not been interfered with my man is naturally rich in nutrients and all the micro life that plants need to grow and flourish, it also gives the plants the ability to fight of insect and disease attack, a good reason for the worms existence, if that was not enough, the worm has also been designed to burrow around in the soil, particularly in the vicinity of plant roots, creating tunnels that allow moisture and air into the soil for plants to use, a pretty convincing argument for their existence.
If there are no worms in the newly created garden then the plants will not have the benefit of the worms existence and will certainly need the intervention by man in the form of adding nutrients, sprays, digging etc. think of how a typical modern wheat field is managed.
Can we just then add worms?
Yes we can but it does have to be done with some thought and preparation, if you just toss on a few handfuls of worms and hope for the best it is likely to fail. We often hear that the soil is compacted and the customer hopes that the worms will break this up along with getting rid of the rubble and concrete also buried! unfortunately worms will not do this, any potential site for adding worms to will need to have any compaction broken up, rubbish including rubble etc must be removed the worms need food, this is the organic matter they would find naturally, in a new garden it must be provided by incorporating it into the soil BEFORE adding worms, it can be in the form of well rotted manure, garden compost or leaf mould or similar materials of a non chemical nature, we recommend this should then be left for a year to settle down and mature, during this period, where possible, a good layer of mulch and or compost should be put on the surface making sure the soil is damp and retains this moisture, then consider adding worms.
Flower and shrub beds
Wherever possible, a “no dig” policy should be established, worms do not like to be disturbed, in shrub and flower beds this is not usually difficult and any subsequent digging to plant would not be a problem, for the worms to thrive it is essential that the mulching continues. Sprays and chemicals are all detrimental to worms and should be avoided.
This is not always so easy, we still have this traditional need to dig but if this is kept to a minimum then the worms will be fine, the more worms the less need to dig except maybe when actually planting. The incorporation of organic compost and manures (old) is still essential, not only for the worms but for the health of the plot and its plants, again, chemical sprays and liquids must be avoided.
When the plots are ready to receive the worms, they must be added by planting, if they are just spread on the surface, many if not most will be lost, the birds will have a field day! Worms are reluctant to burrow down into unknown territories, they don’t know what they might meet so they tend to stay on the surface and head for any dark or damp spots possibly where you do not want them.
If they are on the surface too long the ultra violet light in daylight and sun can severely damage and eventually kill them therefore it is essential they are “planted”. To do this, calculate the area in square meters or yards, work on 3 or 4 holes per yard/meter, dig out a trowel depth hole, add a bit of water and compost, pop in a pinch or so of worms, roughly dividing up the weight or quantity of worms purchased by the number of holes dug, always then cover over the hole with the soil.
Worm colonies are recommended for several reasons, they do not have to be planted immediately on arrival, they make the number of holes to be dug much less (one per 1 or 2 square metres) thereby saving time and effort, the worms are not suddenly introduced to a new environment that they are unfamiliar with, the colony container gives them a safe and secure environment until they are happy to venture forth, job done!
What quantity and species should be planted?
Sadly there are very few species of worms available commercially, many are not available simply because there is no demand, the ones that are available are Lumbricus terrestris, our largest worm, Eisenia hortensis a soil dwelling/compost dwelling worm, Eisenia foetida and Eisenia andrii both being mainly compost worms, all of these worms will live in soil but the “composting” worms will need good volumes of organic matter (which should be incorporated in to soils anyway) to thrive.
The quantity of worms required is not an exact science, as a rough guide you should be aiming for the following:
Introducing Lumbricus terrestris – this would be around 5 worms per square metre minimum, this is a guide only and the quantities can be varied according to budget, however, it should be noted that too few are likely to fail, these are the deep burrowing worms.
Introducing Eisenia hortensis, Eisenia foetida and Eisenia andreii (usually supplied as a mix) these should be planted at around 10 – 20 per square metre as a minimum, there are roughly 1000 per kilo for pricing purposes.
If you are using the Worm Colonies then base your calculations on a minimum of 1 colony per 2 square meters surface area.
The quantities are governed by surface area NOT depth.
I hope this has been useful, please feel free to copy and download for your own private use. Strictly no commercial use or reproduction without our express, written permission.