Abstract：Taking mature cassava slag as main raw material，mixing it with peat，vermiculite and perlite
by different volume ratios into 12 substrate ratios，this paper studied the physical and chemical properties of
different matrix ratios and their effects on the seedling growth of different kinds of fruit and vegetable taking finished
vegetable seedling substrate in the market as the contrast．The paper also screened out seedling substrate formulas
suitable for the growth of cucumber，tomato and watermelon．The results showed that the physical and chemical
properties of compound matrix of cassava slag，peat，vermiculite and perlite in the ratio of 40∶40∶10∶10（T5
treatment）and 20∶40∶20∶20（T6 treatment）were within the suitable range of seedling growth requirements
for fruit and vegetable．The seedling emergence rate，seedling index，chlorophyll content，root activity，
root volume，root tip number and other growth indicators of fruit and vegetables grown in the 2 matrix formulas
were better than that of the other formulas and contrast．According to the growth condition of fruit and vegetable
seedlings，combined with environmental and economic factors，it is recommended to use T5 treatment with higher
proportion of cassava residues as a special formula for cucumber seedlings in production．While，T6 treatment
can be used as a general formula for fruit and vegetable．