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Top 4 common soil types

Updated: Mar 13, 2020

soil chart

The next time your stuck on a growing question, open up our blog post, and you'll be well on your way to becoming a master grower.


To find out the difference among clay, sand and silts, humus, and loam soils; look broader into types. Three basic particles: sand, silt or clay compose all soils. Vast size variations among these particles affect the properties of your indoor garden. Coarse and largest, sand particles are clearly seen and felt in your hand. Smaller silt particles have smooth, flour-like texture. smallest of all, clay particles can be seen through a microscope. The amounts of these different particles determine whether your soil type is primarily clay, sand or loam.


Clay is stiff, fine grained earth consisting of hydrated aluminosilicates that become flexible when water is added. Clay is commonly mixed with other soil types to create a medium suitable for lettuce.

Top 10 plants that love to grow in clay:

Broccoli - Brussels Sprouts - Cabbage (red & green) - Cabbage (Napa & Savoy) Cauliflower - Kale - Bean - Pea - Potato - Radish

humus soil


Humus is the organic constituent of soil, formed by the decomposition of plant materials, and can be bought in bags at local gardening stores. Most of these products claim to be free of bugs and other living matter, but sometimes this is not 100% true. Don't be surprised if you find a worm or green fly in the package. Humus is also sometimes known as compost, but compost is the final mixture of manure, loam soil, and some other media, with added organic matter. Humus is that added organic matter. Humus mixing is a step towards a more natural soil when mixed with clay, and sand and silts.

sand silt

Sand and silts

Sand soils can be pure sand or a mixture of sand soil. The problem with sandy soil is that it drains water and minerals out too fast. It is a very dry soil and is not suitable for the lettuce grower's needs on its own. Silt soils are nearly the same as sand soils, expect they have a consistency more like clay and darker in colors. Silts hold nutrients well but do not hold water very well. Like sands, they are prone to quick drainage. Like we said, sands and silts are rarly used on their own to grow lettuce and mostly mixed with other types. Its important to know about them and how they are used.



Loam tends to be mix of all of the above. The composition of the mix should be stated on the bag. In fact, in most cases, normal soil purchased in shops has humus, sand, silt, and clay already mixed in. When you buy a bag of soil it is nearly always going to be a loam. Loam is a very fertile soil and for control over the ratios you can even mix your own loam soils.

Loam is soil that contains:

less than 52% sand

28-50% silt

7-27% clay

If you enjoyed this, you might also enjoy these post about grow media:

What would you like to see in a future post? Let us know in comments....

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