How to grow zucchini indoors

Updated February 21, 2017

With container gardens, you can have fresh vegetables all year even when garden space is not available. Zucchini is a summer squash that grows best in full sun and warm conditions. As container culture gains popularity, many new dwarf or small growing varieties of vegetables are being developed; compact zucchini varieties are no exception, and include the culitvars Black Magic, Hybrid Jackpot, Gold Rush and Classic. Grow zucchini indoors all year round. In winter, place the pots in a south facing window where they will get the most sun.

Fill 2-inch pots with soilless seed starting mix. Use a pre-mixed formula available at garden centres or make your own by mixing equal parts vermiculite and peat moss. Dampen the mixture and fill the 2-inch pots.

Place one zucchini seed in each pot and cover it with 1/2 inch of soil. Place the pots in dappled or filtered sun with a temperature range between 18.3 and 23.9 degrees Celsius. Keep the soil around the seedlings damp with frequent light applications of water. The seedlings will germinate in five to seven days and be ready to transplant into a large, permanent container in three to four weeks.

Fill one 5-gallon container for each zucchini plant. Use a well-draining soilless potting mix and fill the pot to 1-inch below the lip of the container. Garden centres sell pre-formulated mixes for indoor vegetable container growing. Alternately, mix your own by combining equal parts loam, peat and coarse clean sand. Add a 14-14-14 liquid fertiliser to the mix. Check the back of the package to determine the correct amount.

Dampen the potting mix with water until it is light and crumbly. Scoop out a shallow hole in the centre of the pot large enough to accommodate the root ball of one zucchini plant. Select the strongest of the zucchini seedlings for planting.

Slide the seedling out of the small pot and place it into the large container with the base of the stem planted at the same depth in the soil as it was in the seeding pot. Fill in around the roots and pat down the soil to secure the seedling in the pot. Place the potted zucchini in a sunny window where it will get at least five to six hours of sun each day.

Fertilise once a week using a fertiliser formulated for complete nutrition. There are many combinations on the market for vegetable growing. A good, basic fertiliser formula like a 5-10-10 or a 10-10-10 fertiliser is suitable. Check the package for the correct application amount and method.

Water when the top of the soil feels dry to the touch, usually daily or every other day for container grown zucchini plants. Soak the soil thoroughly at each watering. Place the pot on a saucer or tray to catch water and protect surfaces. Empty the saucer after every watering to prevent water from sitting around the root system.

Harvest the zucchini plants as when they are 3 to 4 inches long and still tender. Harvest continuously as the fruits ripen to encourage the plant to keep producing. Zucchini are ready to harvest 50 to 70 days after planting.


Most houses are kept warm enough all year to grow zucchini inside. A temperature range of 15.5 to 26.6 degrees C is suitable but 65 to 75 is ideal. Always start more seeds than you think you need. Germination rates for zucchini seeds are good but rarely 100 per cent. Zucchini seedlings can be purchased from nurseries and garden centres and planted directly into the 5-gallon container.

Things You'll Need

  • 2-inch pots
  • Seed starting mix
  • Peat
  • Vermiculite
  • 5-gallon pot
  • Potting soil
  • Loam
  • Peat
  • Coarse sand
  • Fertiliser
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About the Author

Eulalia Palomo has been a professional writer since 2009. Prior to taking up writing full time she has worked as a landscape artist and organic gardener. Palomo holds a Bachelor of Arts in liberal studies from Boston University. She travels widely and has spent over six years living abroad.