Crystal apple cucumber plants may produce vegetables that look like they belong on the cover of a science fiction novel; the cucumbers, which are native to New Zealand, resemble small, round apples with yellow skin. Inside, the meat is crisp and sweet. The vines of crystal apple cucumbers look like typical cucumber vines. Like many vine plants, crystal apple cucumbers grow best when allowed to climb up a trellis. Crystal apple cucumbers are hardy between USDA hardiness zones 3 and 14. They mature after 60 days. In zones with shorter growing seasons such as zone 3, start plants indoors and transplant seedlings after all danger of frost has passed.
Plant crystal apple cucumbers in the Northern Hemisphere in early spring. Like many seeds that are sown directly into the soil, you can plant crystal apple cucumbers just after your last yearly frost date. In most of the United States, this is between March and May. Mound up a hill of soil and create a drill hole for your crystal apple seeds. Plant three seeds per hill. Place each seed in the ground approximately three times deeper than the seed at its widest point. Cover the seed and water well.
Check the ground daily and water anytime the soil feels dry. Crystal apple cucumbers require lots of water to maintain their sweet flavor. The plants will germinate after eight days.
Thin cucumber sprouts after the plants until just the strongest sprout is growing on the mound. Provide a trellis for the plants to grow up. Crystal apple cucumbers grow well on a simple string trellis attached to a bamboo stake.
Harvest crystal apple cucumbers when they are palm-sized. Pick cucumbers daily and do not leave any on the vine. Crystal apple cucumber vines will stop producing cucumbers if any are left on the vine to rot.