LOS ANGELES—A customer came in to buy fertilizer on Feb. 23 at GreenCoast Hydroponics, a warehouse popular with cannabis growers near North Hollywood. The prices were so high, he walked out. The record cost of fertilizer and other supplies is starting to take a bite out of business, according to the store manager. The store’s sales may be down by about 10 percent this year, sales manager Nate Honda told The Epoch Times. An average bag of soil cost $12 at the store six months ago. Now, customers are paying $14 to $15 per bag. The warehouse was stacked with pallets of soil products for all kinds of growers. Ocean Forest soil is the most popular, Honda said, taking a few minutes away from helping the customers who streamed in all morning. The store still sells about 500 to 600 bags of soil every day to commercial clients and small …