Here is a video of the engine. There are marks on the ball to make it's rotation easier to see. You will notice that at the start I hold the ping-pong ball in my hand very briefly so the liquid nitrogen will boil and start the rotation quickly.
They can be planted in the spring around your last frost date. Gladioli bloom about 90 days (three months) after they sprout in spring, so the bloom time really depends on when you plant them. In warm climates, where they stay in the ground year-round, gladioli bloom anytime from late spring (deep South) to midsummer (middle South).
Some varieties of coleus may produce their best colour in light shade, while others look best in bright lighting. Sowing: Sow all year round or in Late Spring for outdoor plants Sow all year round for pot plant . For the garden, sow 10 to 12 weeks before the last expected frost , they will then be well developed when it is time to plant them outdoors. Sow seeds onto a layer of moistened, sterile potting soil in a shallow tray, do not cover as they need light to germinate.