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).
Is it too early to plant my caladiums? -- S.T., Houston. A. The bulb planting calendar that's geared to holidays says we can plant caladiums around Easter, so you could begin planting the tubers the first week in April -- if it is warm. Ideally the soil temperature should be around 70 degrees. Cover the tubers with an inch of slightly acidic, loose, well-draining soil. Plant with the smooth side down.