How to Grow Zucchini: You've Been Doing It All Wrong.

You probably think you already know how to grow a zucchini plant but if you live in North America ... you might not.  Here's a way of growing zucchini to make your plants live longer, take up less space and produce more. 

Zucchini is touted as one of the easiest and most prolific vegetables you can grow in a home garden. And that's mainly true. This growing guide will fill in every blank and answer most of the questions you've ever had about zucchini.

Planting zucchini can be done by any fool. You stick a seed in the ground, go inside to watch television for a few weeks, come back outside and BOOM you have a zucchini plant.

But there are a few things about growing zucchini that you probably don't know. Even I, who has a 40' x 40' vegetable garden, who is a contributing writer for The Old Farmer's Almanac didn't start using this technique until a few (maybe a decade actually) years ago.

1. Zucchini need to be pruned and staked.  For real. Like you prune a tomato.

2. Zucchini can be planted VERY close together. 1 per square foot but remember to make sure your soil is amended for that. (lots of compost or some organic fertilizer)

3. Powdery Mildew CAN be halted.

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The most interesting fact about zucchini is they can do complex math equations.

No they can't. We're very alike zucchini and I.

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If you're looking for a really rewarding challenge that's a little more mysterious than zucchini take a look at my expert tips on how YOU can grow luffa sponges at home.

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Growing zucchini

• Zucchini are a summer squash so these tips and techniques can be applied to any other summer squash like yellow, crookneck or patty pan.
• Seeds or seedlings can be planted into warm soil at the start of summer (typically the end of May).
• Zucchini fruit develop around 50 days after planting. Once the fruit form, zucchini grow very quickly - especially if it's hot out and they get plenty of water.
• Zucchini don't need a lot of soil amendments. Add 2-3 inches of mature compost on top of your planting site and you'll be rewarded with enough zucchini to fill a clown car.

When to plant Zucchini

• Zucchini are heat loving plants so wait until your soil temperature is above 65℉ (18ºC) to plant out seeds or seedlings.
• You can plant 2 weeks earlier if you lay plastic mulch on your planting area which will increase the temperature of the soil below by 10 degrees. Garden centres sell black plastic mulch, which is often biodegradable but any black or clear plastic will work. Get biodegradable black mulch here.
• Planting 2 weeks earlier also means you will be harvesting 2 weeks earlier!
• If you're starting seeds indoors, plant them 3 weeks before your last frost date.*

Because zucchini grow so quickly and don't always transplant well there's really no need to start them inside. They usually do better when direct sown under plastic mulch. Just cut an X into the thermal plastic and push the seed down into the soil through it.

Where to plant

• Zucchini needs to be planted in an area that gets 6-8 hours of sun per day.
• Plant near companion plants like beans and peas (which fix nitrogen into the soil).
• Surround zucchini with pollinating flowers like borage, catmint, dill or dahlias to attract pollinators to that area of the garden. (zucchini need pollinators to hop from their male to their female flowers in order to produce fruit)

How to plant zucchini

Supplies

• Zucchini seeds or seedlings
• Large pot or 1' square of soil
• Water

Instructions

STEP 1 - Make sure your garden is weed free and rake it smooth.

STEP 2 - Apply a 2-3" layer of compost on top of the soil and rake smooth. If you're laying down plastic mulch to speed up your planting and harvest date, now is the time to do it.

STEP 3 - When the soil registers 65℉, plant seeds to a depth of 1" which is about the distance from the tip of your index finger to your first knuckle. For seedlings, plant them so the soil line of the seedling matches the soil line of the garden. Then push the seedling down a little to firm it and add more soil to fill the space if needed.

STEP 3 - Cover the seed with soil and water well. Make sure the soil doesn't dry out at all until you see the seeds sprout.

STEP 4 - Maintain moisture for the rest of the summer with at least 1" of water a week. Zucchini LOVES water. And don't worry about getting water on the leaves. Water doesn't exacerbate or cause powdery mildew. In fact, water helps wash it off of the plant. Powdery mildew is triggered by dry conditions - not wet.

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THESE are the two tricks to growing zucchini better than anyone else: staking & pruning.

How to stake zucchini

Growing zucchini vertically might not be your first thought but it's exactly what you should do.

North American gardeners haven't really adopted this technique yet but it's common in Europe.

STAKING

1. Drive a 4-5' stake into the ground before planting, so you don't damage the roots. I use lightweight coated metal stakes.
2. Plant your seed or seedling right next to the stake so as it grows you can tie the stem to the stake.

You may not have noticed it before, but a zucchini plant only has one stem. That stem is just usually sprawled and dirty on the ground covered in decaying leaves. So you can't get a good look at it.

But trust me. Zucchini have one stem, that can be staked just like a tomato. 

The earlier you do it the easier it is though.

Above you can see a zucchini plant that's only been staked and tied once, earlier in the season with the rest of the growth just flopped over.  The leaves are being eaten by bugs, there's no air circulation and the lower leaves near the soil are getting powdery mildew.

Here's the same zucchini plant after staking it properly and removing all the lower leaves.

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Just like tomatoes, zucchini benefit hugely from pruning.  They'll be susceptible to less disease, have a more open formation that allows easier access for bees to pollinate and they'll take up less space.

How to prune zucchini

Why prune?

• The developing zucchini gain all their energy from ONLY the leaves growing above them. The leaves below, are just taking energy away from the rest of the plant.
• Pruning away diseased and damaged leaves helps prevent and slow powdery mildew by creating greater air circulation.
• Pruning away the larger, lower leaves that aren't contributing to the plant means you can plant more zucchini in a smaller space.
• The flowers are easier for bees and butterflies to access.

PRUNING

1. Locate the lowest growing zucchini on the plant.
2. Cut off all of the leaves growing from the stem below that zucchini. Cut right close to the stem.
3. As the plant grows continue cutting off any leaves that are below the lowest growing fruit.

Fun Fact

Zucchini leaf stems are hollow UNTIL they get to the stem of the plant. There they turn solid again.  Prune your zucchini leaves right up to the stem of the plant so you don't have any of the hollow stem left.

• Hollow stem portions can harbour disease and bugs so make sure you get right close to the plant stem when removing the leaves.

See the difference from the left photograph and the right one? 

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Spacing Zucchini

Plant zucchini 1' apart. Rows should be spaced at 1.5' apart.

A lot of guides tell you to place zucchini plants at least 24" apart. You don't need that much room between them.

If you're staking & pruning them this is all the room they need.

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SOME MORE GOOD VEGETABLE TIPS FOR YOU

SAVE Your Zucchini and Squash from Squash Vine Borer

My Leek Growing Technique - Based on Eliot Coleman's

Make Paper Pots with a Wine Bottle

Make a Soil Grader for Levelling Your Garden from a Wood Pallet.

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Disease

Powdery Mildew

• It's the kiss of death for zucchini plants, but luckily it's a long, slow, torturous death. 
• Most zucchini plants seem to be able to withstand powdery mildew for quite a long time - months even.
• To help prevent powdery mildew, stake and prune your zucchini like I've shown you.
• If you notice powdery mildew has made its way onto your plants you can spray with this homemade Powdery Mildew spray for zucchini. It's just vinegar and water but it works.

Pests

The number 1 killer of zucchini plants are squash vine borers. These maggoty stem eating bits of grossness can kill a plant before you even realize it's sick.

Squash vine borers bore their way into the stem of the zucchini along the soil line and then proceed to eat the entire plant from the inside out.

There's usually only one vine borer per stem, so all you have to do is check your stems for signs of it at the end of June and into the summer.

I have a whole post on how to remove squash vine borers from your zucchini, winter squash, pumpkins and other gourds.

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Apply what you've learned here and you'll have your biggest zucchini crop ever.

You might be wondering why would you want them to produce even more?  Zucchini are already insanely productive. Well, because of the obvious.  They’re fun to throw through people’s open car windows during zucchini season. 

Zucchini may not be able to do complex mathematical equations but they can add up like nobody's business.

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