Germinating Zucchini Seeds Indoors Using a Glass Dish

Zucchini is easy to start from seed. Zucchini seeds germinate quickly and without excessive warmth. As a cucurbit, zucchini is sensitive to any root disturbance, such as from transplanting. Surface cultivation, digging, harvesting root crops, thinning, or weeding near established plants may also cause root disturbance to cucurbits. For both these reasons, GardenZeus recommends growing zucchini from seed, not transplants.

Zucchini and other summer squash can be seeded directly outdoors, when daytime temperatures are at least 65°F and frost risk is low.

While transplanting squash is tricky, it’s easy to germinate seeds indoors for immediate planting outdoors. Gardeners who live in areas that receive frost can begin germinating zucchini seeds one week before their last frost date. Space seeds widely on a moist paper towel in a covered glass dish.

Zucchini seeds before germination

Monitor seeds daily and plant directly outdoors as soon as a root emerges. Germination is faster with bottom heat, such as from an appliance or germination heating mat or pad (do not germinate seeds with heating pads meant for human use, which are not designed to accommodate moisture or use for long periods). Use care when handling tiny, delicate roots. If roots have grown into the paper towel, tear it carefully and plant the germinated seed with paper towel attached.

Zucchini seeds after germination

Generally, summer squash should germinate within a week if kept moist at temperatures of 70° to 95°F. If more than a week has passed under these conditions, investigate your seeds. Something may have gone wrong or you may need to replant.

GardaenZeus has complete, customized information for growing zucchini and summer squash in your area. To get started, enter your zip code and then go to zucchini or summer squash.

Other articles of interest relating to zucchini include:

GardenZeus Quick Tips: Pollination Issues With Zucchini and Other Summer Squash

Growing Summer Squash (Including Zucchini) in the California Home Garden