How to Grow Zucchini Indoors

Zucchini has more potassium than a banana! They are fairly recent to the US, being brought over from Italy in the 1920s.

Best Zucchini Varieties to Grow Indoors

Zucchini has two types: vining and bush. Bush types are more suited to grow indoors than vining ones. We’ve listed the most popular varieties for you below:

Best Setup for Zucchini Plants

You’ll need:

• Planter: Ceramic Self Watering Planter (preferred) or pot that is at least 12″ / 5 gal.
• Soil: Standard Potting Mix
• Plant Food: Herb Blend. This should be high in nitrogen (with NPK numbers like 10-5-5).
• Grow Light: A strong grow light that can give the equivalent of 7+ hours of direct sun [DLI of 21+ mol/m²/day].

Preparing Your Planter & Watering Schedule for Zucchini

Zucchini plants do well in moist soil conditions. Using a Ceramic Self Watering Planter can help maintain consistent moisture levels. To set one up:

1. Fill the planter with dry soil from the bag, gently tamping down the top.
2. Dump the soil into a large mixing bowl and add water until the soil is moist but not sopping wet (about ½ cup).
3. Mix in 1 tablespoon of Herb Blend Plant Food.

If you are using a regular pot, it should be a little bit bigger (at least 12″ / 5 gal) and will need drainage holes to prevent overwatering. Let the top of the soil dry out between watering.

Starting Your Zucchini: Seed vs Propagate

Zucchini plants are best started from seed in the area they will grow to their full size (known as “direct sowing”). They’re not practical to propagate from cuttings and don’t handle transplanting well. Fortunately, starting from seed is simple and they sprout quickly!

How to Plant Zucchini Seeds

Zucchini grows quickly from seed. Plant 1 site in a 12″ / 5 gal container. In larger containers, space sites 24″ apart. For each site, plant 2 seeds 1″ deep. Keep the soil warm (68-95°F, ideally 70°F). Sprouts typically appear in 10 days but can be as quick as 7 days or as long as 14 days depending on your conditions.

Why Starting Zucchini Doesn’t Make Sense

Zucchini are short-lived plants and prone to root rot. Even under perfect conditions, they lack the genetic makeup to readily produce roots from their stems.

Where to Grow Your Zucchini Plants

Zucchini plants have the highest light needs of any plant, so unless you have a totally unobstructed southern-facing window and plan on only growing in the summer, you’ll need a grow light. We recommend taking advantage of your bright window (sunlight is free and great for plants!) and supplementing it with a grow light. For an introduction to grow lights, check out our post on grow lights for indoor gardeners. We’ve also got a buying guide for screw-in types, but to keep things simple, we recommend the 24W Screw-in Bulb by Sansi.

How Bright Should Your Grow Light Be?

Zucchini plants need the equivalent of 7+ hours of direct sunlight [DLI of 21+ mol/m²/day] to grow their best. The 24W Sansi bulb should be placed 6 inches away from the top of the plant. This will give your PPFD (the standard measure of brightness) of 500 μmol/m²/s.

How Many Hours Per Day Do Your Zucchini Plants Need Under a Grow Light?

Zucchini plants are what’s known as “day-neutral” so can grow under a range of daylight lengths. To ensure they get enough light, set up a timer to leave it on for 14+ hours per day.

Zucchini Plants Grow Faster in Warmer Temps

Zucchini plants are "warm-weather crops" and like temperatures right around 70°F. They will grow fine in conditions between 60 and 100°F but can lose their fruit if it drops below 40°F. Too hot, and they will drop their blossoms, wilt, and stop ripening. Most homes are in a good range – and a south-facing sunny window can help get a plant the extra heat if needed.

Week 1-2: Check for Sprouts

You could see seedlings in as little as 7 days (though 10 days is more typical). If it’s been 14 days and you still don’t have any sprouts, it’s likely that your setup is too cold.

Week 3: Thin Your Seedlings

Thin your planter to only have 1 seedling per site – leaving the largest plant. If you are using the recommended planter (at least 12″ / 5 gals) this will mean you’ve got 1 plant after thinning. By getting rid of the smaller seedlings, you’re allowing the biggest and strongest one to flourish by reducing its competition for water, food, and space. If your seedlings are under 2 inches, stretching out, or folding over, it’s likely that they don’t have quite enough light.

Week 4: How to Prune & Trellis Zucchini Plants

Zucchini plants are vines that will continue to grow, so a monthly trim will be a necessary part of your care routine. At about the second month, or when you have 5 branches and a growing tip, cut (or just pinch) off the main stem above the 5th branch. By removing the growing tip, you’re having the plant focus its energy on those 5 branches. There are several support options, ranging from cages to stakes, but we like to train those 5 branches up a fan trellis with plant clips.

After this, pruning and trellising is more of an art (fortunately an art that’s hard to mess up) but the general things you’ll want to look out for are:

1. Little leaves growing out of the “V” where a branch meets the main stem. Snap these “suckers” off right at their base.
2. The main stem going past your grow area. Pinch off the growth tip where you want it to stop.
3. A heavy cluster of Zucchini starting to form. The weight can snap the vine, so clip right above the cluster to the trellis to avoid this (mildly heartbreaking) event.
4. The plant getting so dense that light and air can’t get in. Keep up with interior pruning to have a tidy “bonsai” Zucchini plant.

Month 2+: How to Pollinate Your Zucchini Flowers

We recommend self-pollinating Zucchini, as it’s easier than manual pollination. Wait until the flowers open, then give them a slight shake or “rub the nose” of the flower.

Month 3+: How to Harvest Zucchinis

The rule for these is to “pick um often and pick um all.” Zucchini are at peak crispness for a short time, so pick often to catch the small window of the best flavor. If you miss a zucchini and it grows to maturity, the plant may end its life cycle early. By preventing seed production, you keep it producing vegetables longer.

Month 6+: End of Life

Indoor Zucchini plants can last for up to half a year, but eventually, they’ll tire out. Once you see a big drop in productivity despite giving it sufficient plant food, it’s time to start over.

Shop This Blog

The right supplies can make caring for your plants easier. Through our grow tests, we’ve found these products to be the best for indoor Zucchini:

Best Containers for Zucchini: Ceramic Self Watering Planters

Plants thrive on consistent moisture but can suffer if they’re waterlogged. A semi-porous ceramic self-regulates ideal conditions. Our favorite is the COSWIP planter. Runner up is the XS Self Watering Planter by Wet Pot.

Best Soil for Zucchini: Standard Potting Mix

Zucchini likes a rich and moist root zone. We recommend the Potting Mix by Rosy Soil.

Best Nutrients for Zucchini: Herb & Lettuce Blend

Zucchini likes nutrients high in nitrogen (with NPK numbers like 10-5-5). We recommend Joyful Dirt All Purpose.

Best Light for Zucchini: DIY or Soltech

There is a very small chance that you have the bright windows needed to grow these without a grow light. If you are looking for a higher-end option, we love the Aspect Light by Soltech. For a more affordable option, a DIY setup using a 24W Screw-in Bulb by Sansi with a Clamp Light and Mechanical Timer works well too. Check out our complete guide on a DIY setup for less than $40 or our buying guide for screw-in bulbs.