I'm trying to grow some A.Terreus on some Czapek-Dox plates
Here's my recipie:
1.5004g Sodium Nitrate
249.8mg Potassium Chloride
249.8mg Magnesium Sulfate Heptahydrate
4.9mg Iron(II) Sulfate Heptahydrate
500.3mg di-Potassium Hydrogen Phosphate
500mL distilled H2O
Everything but the dextrose gets dissolved completely in boiling water. Then this is autoclaved at 121C for an hour. Then we let this cool until it is cool enough to touch, and the 15g Dextrose is added and mixed until dissolved. The pH is then adjusted to 4.0 with 1M HCl. The plates are poured, 25mL each, and they are allowed to solidify at room temperature. The plates are stored at 4C.
My plates end up much too soft. It is impossible to streak these plates without completely decimating them.
The fungus does grow on these plates. The plates just have a significantly different consistancy from the "store-bought" plates of the same recipie.
Can anybody guess what we're doing wrong?