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).
Typically the best time to plant turnips is in the fall for most locations (in the US). You can plant them in the early spring about 4 â 6 weeks before the last frost date for your area. If you plant them in the fall, sow the seeds about 70 days before the fall frost date for your area.