Do not worry about mycelium on and in the soil. If your almond seed was moldy then they just won't germinate. Soil is always full of fungal spores. When the soil gets disturbed, water added, some of those spores will grow. No big deal. If your seeds were moldy they just won't germinate. Nothing more insidious.germination of almond seeds Germination of almond seeds
DO NOT add anything right now! No vinegar, baking soda, my goodness. One actually lowers pH possibly making your soil uninhabitable by any plant and the latter raises the pH. pH is a big deal. One never adds anything to the soil unless they have a soil test and knows soils, chemistry and plants!
More than likely the mold, if any on the almonds, is NOT the fungus/mycelium you are seeing in the soil. You can't believe the amount and diversity of fungal spores in garden soil!
