And, since we like to grow our broccoli sprouts in low-light and warm areas (indoors), this makes mold even more likely to grow. To grow broccoli sprouts, start by combining your seeds with filtered water in a glass jar. Continue Shopping. Nutrient dense broccoli sprouts are rich in vitamins, minerals, antioxidants, and protein. For many, this will mean that the Purple Sprouting broccoli seeds need to be started indoors 6-8 weeks before the last frost or directly seeded 4 weeks before the last frost in late winter/early spring. Using cheesecloth or mesh will allow airflow into the jar, but will keep dirt, bugs, and particulate out. Super Spicy Greens Microgreen Mix. {"smallUrl":"https:\/\/www.wikihow.com\/images\/thumb\/f\/ff\/Grow-Broccoli-Sprouts-Step-1-Version-4.jpg\/v4-460px-Grow-Broccoli-Sprouts-Step-1-Version-4.jpg","bigUrl":"\/images\/thumb\/f\/ff\/Grow-Broccoli-Sprouts-Step-1-Version-4.jpg\/aid1339922-v4-728px-Grow-Broccoli-Sprouts-Step-1-Version-4.jpg","smallWidth":460,"smallHeight":345,"bigWidth":"728","bigHeight":"546","licensing":"