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How long to grill zucchini and squash in foil is about 15 to 25 minutes on a medium-hot grill, depending on how thick you slice them.
That’s the quick answer, and it’s honestly one of the easiest ways to get tender, flavorful veggies with almost zero cleanup.
If you’ve ever wondered how long to grill zucchini and squash in foil without turning them into mush, you’re in the right place.
The foil packet traps steam and heat, so the zucchini and squash cook evenly while soaking up whatever seasonings you add.
In this post, we’ll break down the exact grilling times, the best temps, and a few tips so your foil-grilled zucchini and squash turn out perfect every single time.
Let’s get grilling.
How Long to Grill Zucchini and Squash in Foil
Grilling zucchini and squash in foil usually takes 15 to 25 minutes, and here’s how the timing breaks down:
1. Thin Slices Cook in About 10 to 15 Minutes
If you slice your zucchini and squash into thin rounds or half-moons, they’ll grill in foil in roughly 10 to 15 minutes.
Thin slices steam fast inside that sealed packet, so keep an eye on them after the 10-minute mark.
The goal is tender but not falling apart.
2. Thick Chunks Take 20 to 25 Minutes
When you cut zucchini and squash into thicker chunks or spears, plan on 20 to 25 minutes.
Bigger pieces need more time for the heat to penetrate all the way through.
Flip the packet once halfway through so everything cooks evenly.
3. Medium-Hot Grill Is the Sweet Spot
The ideal temperature for grilling zucchini and squash in foil is around 375°F to 425°F.
That’s a medium to medium-hot fire on most grills.
If your grill runs hotter, the veggies may steam too fast and turn mushy.
Too cool, and they’ll just sit there without getting that nice tender bite.
4. Whole Zucchini and Squash Need 25 to 30 Minutes
Grilling zucchini and squash whole in foil takes a bit longer, usually 25 to 30 minutes.
Prick them with a fork first so steam can escape and they don’t burst.
Whole squash stays extra moist and makes a great side dish with almost no prep.
5. Check for Tenderness, Not Just Time
The best way to know how long to grill zucchini and squash in foil is to test them with a fork.
When the fork slides in easily, they’re done.
If there’s resistance, seal the foil back up and give them a few more minutes.
How to Grill Zucchini and Squash in Foil Perfectly
Getting the timing right is only half the battle.
Here’s how to set yourself up for foil-grilled zucchini and squash that taste amazing:
1. Slice Evenly for Consistent Cooking
Cut your zucchini and squash into pieces of the same size so they cook at the same rate.
Uneven slices mean some pieces turn to mush while others stay firm.
Aim for rounds about 1/4 to 1/2 inch thick, or chunks around 1 inch.
2. Toss With Oil and Seasonings First
Before sealing the foil, drizzle the zucchini and squash with olive oil and toss with salt, pepper, garlic powder, or your favorite herbs.
The oil helps them cook evenly and keeps them from sticking to the foil.
It also helps the seasonings cling to every piece.
3. Use Heavy-Duty Foil and Seal Tight
Heavy-duty foil holds up better on the grill and won’t tear when you flip the packet.
Fold the edges tightly to trap the steam inside.
That sealed environment is what makes grilling zucchini and squash in foil so effective.
4. Leave a Little Room Inside the Packet
Don’t cram the zucchini and squash into a flat, tight layer.
Give them a bit of breathing room so the steam can circulate.
A single layer or a loose pile works best.
5. Open the Foil at the End for Char
If you want a little smoky char, open the foil during the last 5 minutes of grilling.
This lets the direct heat hit the zucchini and squash and gives them those nice grill marks.
Just don’t walk away, because they can go from perfect to burnt fast.
Common Mistakes When Grilling Zucchini and Squash in Foil
Even simple recipes can go sideways, so watch out for these common slip-ups:
1. Overcooking Until They’re Mushy
Zucchini and squash have a high water content, so they soften quickly.
Pulling them off the grill a minute or two early is better than letting them turn to mush.
2. Skipping the Oil
Without oil, the zucchini and squash can stick to the foil and dry out.
A light coating is all you need.
3. Not Preheating the Grill
A cold grill throws off your timing and leads to uneven cooking.
Preheat for at least 10 minutes before the foil packets go on.
4. Forgetting to Flip the Packet
Flipping once halfway through helps both sides cook evenly.
It’s a small step that makes a big difference.
5. Adding Too Much Liquid
Zucchini and squash release their own liquid as they cook.
Adding extra water or broth can turn your veggies into a soggy mess.
A splash of lemon juice or a pat of butter is plenty.
So, How Long to Grill Zucchini and Squash in Foil?
Grilling zucchini and squash in foil takes about 15 to 25 minutes on a medium-hot grill, depending on how you slice them.
Thin slices finish in 10 to 15 minutes, thick chunks need 20 to 25 minutes, and whole squash takes around 25 to 30 minutes.
Use a fork to check for tenderness, and don’t be afraid to pull them off early.
Now that you know exactly how long to grill zucchini and squash in foil, you can fire up the grill and enjoy tender, flavorful veggies with almost no cleanup.
Happy grilling.