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kath

Katherine
Dishing the Dirt on CP soils


There is a lot of controversy over just which soils are best for certain types of CP's. Some growers prefer perlite, some prefer sphagnum, some plants just really don't seem to care, so exactly what is it that makes a type of soil good for CP's?

Read on and find out!

CONTENTS:

Soil Types
Aggregates
What features do CP soils have to have
What soils do what?
Which soil is best?
What aggregates do what?




Soil Types

This is a list of all soil types you can grow carnivorous plants in. Some of them are more suited to particular plants, some are general, but all of them can grow some carnivorous plant safely. Only general types are listed, eg: chopped sphagnum moss does not appear because it is a type of sphagnum moss. Types of soil types are listed further in the article. There are obviously some other types of soil you can grow carnivorous plants in, but these are the more suitable and common of the lot. You can also use these types on their own, with no other additives or other soil types, although this may not be good for the health of the CP.
So here's the list of reccomended soil types:

Sphagnum Moss
Peat Moss
Clay Balls or Pellets

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Aggregates

On top of the basic soil types there are also several additives that people can add to their CP soil. The additives are called aggregates, and they are added to the soil to improve it, using their various, and sometimes hard to comprehend 'qualities' and 'features'. Aggregates can be used on their own as soil for carnivorous plants, but generally this is not a particularly intelligent thing to do, as not many aggregates can completely fulfill the needs of carnivorous plants on their own. More commonly aggregates are added to various base soil types to improve them. They are not always needed, but can often be of great help.
Here is a list of commonly used, or suitable aggregates that have been recommended:

Pumice
Perlite
Zeolite
Fir Bark
Lava Rock
Silica Sand
Vermiculite
Gravel
Coconut Husk Chips
Charcoal

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What features do CP soils have to have?

Carnivorous Plants have adapted over a very long period of time to live in certain conditions. Most of them have adapted to live in bogs or very wet ground, and it these ones that I am writing this article for.

Carnivorous Plants that have adapted to live in bogs will be living in soil that is wet all year round. Where they live it will be very sunny and warm and humid in summer, and depending on the area, it may be cooler in winter and less watery, or it may continue being warm, wet and humid.

Because of all the water around in their natural habitats, most or all of the normal nutrients etc. in the soil have been flushed away or absorbed. The soil is very acidic, with a low Ph. It is lacking in chemicals such as Nitrogen, Calcium, Magnesium and Salt. It certainly isn't subjected to Chlorine or other tap water chemicals.

Here is a list of the must have's for CP soil:


*Must be acidic.
*Needs to have low soil Ph
*Must be able to retain large amounts of water
*Must be able to freely drain to prevent root-rot
*Must allow for high humidity levels
*Must allow oxygen to reach the roots
*Must not clump
*Must not contain too much Nitrogen, salts, calcium, or magnesium

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What soils do what?

There seem to be a lot of different features or functions that CP soil must have, so what soils fulfill these functions? Pro's are listed with a * cons are listed with a -


Sphagnum Moss:
Sphagnum is a genus of between 150-350 species of mosses commonly called peat moss, due to its prevalence in peat bogs and mires. It can be found fresh with live bits of moss included, dried where it is completely moistureless and lightweight, and chopped where it is chopped up. There are also other types.
Attributes:

*Dried sphagnum moss can hold up to 16-20 times it's weight in water
-Sphagnum moss can become waterlogged
-Wet Sphagnum moss is heavy
*Many carnivorous plants grow in Sphagnum in Nature
-Sphagnum moss is in demand and often harvested from the wild
*Acidifies surroundings
*Removes calcium and magnesium from the soil
*Inhibits the growth of fungus and bacteria-fungus and bacteria won't live in it
-Can potentially harbor the chronic fungal disease sporotrichosis which enters the skin via abrasions and cuts
*Insulating material-holds heat

Note: New Zealand Sphagnum moss is a renewably harvested option for those who are concerned about the detrimental effects of removing sphagnum moss. New Zealand moss harvesting is closely watched by the Department of Conservation and is done on a three year basis so there is always enough left to regenerate new growth.
....................................................................
Peat Moss:
Decayed, compacted Sphagnum moss has the name of peat moss. It is formed over a very long time, and there are concerns over it's harvesting as it is a non-renewable source.
Attributes:

*Increases the water holding potential of the surrounding soil
*Soft, easily comprssed
-Can cake and clump
-Can burn easily when dry
-Naturally anaerobic (has no oxygen present)
*Low soil Ph
*Very acidic
-Dry peat can take a long time to become fully saturated and ready for planting
*A non-renewable source, will not last forever if it keeps being taken away from bogs
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Clay Pellets:
This man-made product is often called grow rocks and is an extremely good growing medium. It is made by baking clay in a kiln. The inside of the clay pellets is full of tiny air pockets which makes this a light weight medium.
Attributes:

*Increases oxygen retention of the surrounding soil
*Do not retain too much water, but retain some
-Frequent waterings needed to stop roots drying out
*Lightweight
-Some of the pellets may float on water, so the soil will not stay around the plant's roots
-Can be dusty
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So which soil is best?

Of the three soil types listed, sphagnum moss would have my vote as the best soil. Not only does it retain water just as well as any of the other soils, it is also natural, renewable, and prevents the growth of fungus and bacteria. Peat is just as good, but environmentaly, it would be better to use sphagnum over peat. Clay pellets are also good, but they aren't natural, and don't hold the water that CP's so desperately need as well as peat or sphagunm.
Good soil mixes could be a mixture of sphagnum and clay pellets, the sphagnum to retain water and for it's bacterial and fungal fighting properties, the clay pellets to add drainage and prevent water-logging. Peat and Sphagnum moss could also be a good, natural mix, or peat and clay pellets, or a mixture of all three.



What Aggregates do what?


There are a lot of different aggregates, but are they all necessary? Are any really needed? And what do they all do?

Pumice:
This is a glassy material that is formed by volcanic activity.

Attributes:
*Highly porous-provides plenty of air spaces for roots
*Can hold water
*Increases water holding retention of surrounding soil
*Free-draining
*Does not leach any chemicals
-Can float,if used with no other soil pumice will not stick to the roots
-Abrasive, may damage roots if used in too great a quantity
-Does not hold enough water to be used solely as a soil for CP's
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Perlite:
Perlite is not a trade name but a generic term for naturally occurring siliceous rock. The distinguishing feature which sets perlite apart from other volcanic glasses is that when heated to a suitable point in its softening range, it expands from four to twenty times its original volume.

Attributes:
*Super light
*Sterile
*Easy to use
*Retains some water
*Free-draining
*Can withstand repeated usage
-Contains small traces of calcium
*Prevents soil compaction
-Does not hold enough water to be used as a sole soil type for CP's
-Can be abrasive
...................................................................
Vermiculite
Vermiculite is a natural mineral that expands with the application of heat.

Attributes:
*Sterile
*Non-Abrasive
*Very light
-Slightly alkaline
*Aerates the soil well
*Insulating
*High water holding capacity
-Does not hold enough water to be used without other base soils for CP's
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Zeolite
More than 150 zeolite types have been synthesized and 48 naturally occurring zeolites are known.
Natural zeolites form where volcanic rocks and ash layers react with alkaline groundwater. Zeolites also crystallized in post-depositional environments over periods ranging from thousands to millions of years in shallow marine basins. In agriculture, clinoptilolite (a naturally occurring zeolite) is used as a soil treatment. Some Zeolite is made from thermally altered clay.

Attributes:
*Absorb up to 55% of their weight and slowly release under plant demand
-May not hold enough water for CP's
*Absorbs gases, liquids and odors
*Improves water retention
*Absorbs calcium from soil
*Absorbs nitrogen from soil
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Fir Bark
Chips of bark from fir trees.

Attributes:
*Usually cheap
*Fairly lightweight
*Doesn't compact
-Decays
-Compacts as it decays
*Fir bark absorbs nitrogen
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Lava Rock
Dried magma from a volcano.

Attributes:
-Jagged and abrasive
*Black lava rock absorbs heat and warms up the soil
*Does not rot, but does slowly decompose into 'Lava Sand'
*Retains water
*Allows air to reach the roots
-Does not retain enough water to be used solely on it's own for CP soil
-Accumulates salts
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Charcoal
The product left over from burning wood.

Attributes:
-Collects salts
-Makes soil alkaline
-Raises soil Ph
*Does not break down
*Can be used as a substitute for perlite in water and air retention qualities
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Silica Sand
Fine granules of silica, the component quartz is made out of.

Attributes:
-Abrasive
*Porous, allows good drainage
*Allows nitrogen to be slowly leached out of soil during watering
-Does not retain water needed for CP's
*Allows good aeration of the roots
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Gravel
Gravel is any rock that is of a certain particle size range.

Attributes:
*Improves drainage
-Does not retain water
-Can be abrasive
-Often unknown rock type
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Coconut Husk
Coconut coir is what is mentioned. Coir fibers are found between the husk and the outer shell of a coconut.

Attributes:
*Hydrates rapidly
*Increases water holding capacity
*Porous, provided plenty of air spaces
*Can replace fir bark
-Can contain salt which has a detrimental effect on CP's
-Inconsistent, unreliable performance
*Free of bacteria and fungal spores
*Conatains no nutrients
*Retains 8-9 times weight in water
*Could be used as a substitute for peat, vermiculite, perlite or pumice, but is of lesser value to CP's
-Eventually breaks down
*Breaks down slowly
*Lightweight
*Odorless
-Non acidic
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The important thing is to work out what type of soil your plant likes, then you can choose any mixture of soils and aggregates for it.

Hope this helps!

Kath
 
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