**9.1 Technical specifications for substrates**

According to [11–13] substrates must have the following properties:


*Soilless Cultivation to Secure the Vegetable Demand of Urban and Peri-Urban Population DOI: http://dx.doi.org/10.5772/intechopen.102695*


Substrates, such as rockwool, cocopeat, clay granulates, pumice, sand, Irish peat, and perlite, are able to meet the above specifications [14, 15].

#### **9.2 Substrate categories**

Ideal substrate should fulfil four important roles *viz.,* (i) should act as a reservoir for plant nutrients, (ii) should hold enough water, (iii) provide good aeration, and (iv) physical support for good plant growth and development. Only a few substrates that are available in the market generally support all the four functions as mentioned above but at a very limited level. However, some of the soilless media may not support all the functions, i.e., sand gives good physical support and


#### **Table 2.**

*Various soilless culture media and crops grown.*

aeration but is very poor in nutrient and water supplying capacity. Various growing media and crops grown in different countries are given in **Table 2**. Based on the source or origin of substrates, soilless growing media may be classified into two groups namely organic and inorganic medium. Peat moss, wood residues, sawdust, barks, and cocopeat are some of the widely used organic substrates in soilless cultivation. Other substrates, such as perlite, sand, vermiculite, calcined clays, pumice, and rockwool are most commonly used inorganic substrates in hydroponics or soilless cultivation.
