In a moment of synergy I’ve had three people ask me for tips on growing zucchini this week. Even though I clearly and patiently explained to them that this is my first gardening season and they’re taking their zucchini’s life into their hands when they listen to anything I say. But I am good at synthesizing information from various sources and since I crammed my brain full of gardening knowledge I figured I’d post it here for anyone else who is even more clueless than I am.
Zucchini Growing Guide
If you’re starting zucchini from seed anywhere in the second week of May to June 1 is a good time to start. Zucchini grows fast and you don’t want to start it too early like tomatoes or you’ll have a huge bush on your hands in no time. You only need to give it a couple of weeks head start if that, and really given how fast it grows (my package of seeds says 40 days to maturity), it may be better to direct seed it since it doesn’t particularly like to be transplanted.
To start the seed follow the very basic instructions common to all seeds – take your peat pod, moisten it, make a small pencil hole in the middle and plant the seed about ½ inch down. Cover it with peat on top, press the peat all around the seed and place in a warm spot – say over your fridge, or an empty oven. That you won’t forget to check before turning on. Zucchini seeds like a really warm soil to germinate in, so a chilly window sill may not be the best spot for it.
Immediately as it germinates (which may take 4-10 days), place it under a bright fluorescent light, at least 25 watts strong. I found great inexpensive T5 sunlight tubes at Spruce It Up Garden Centre which is the only place I’ve seen them so far, and one will work for a whole tray of seedlings. Make sure it doesn’t ever dry out, and after it gets its first set of true leaves begin feeding it with a mix of kelp and fish fertilizer at one third to half strength every couple of weeks. If it grows more than a couple of inches before the weather is nice, replant the whole peat pod into a four inch container.
About ten days before going outside, let your plant acclimatize to the great and dangerous outdoors by hardening it off. Since so far the plant has led a pampered life – warm, sheltered and moist it will have broader leaves than an outdoor plant to capture more light, and weaker stems from lack of exercise due to wind motion. Many plants take transplanting hard enough, zucchini being one of them, and transplant shock will set them back severely – they may not grow for a week or two, produce less fruit, and succumb to diseases and predators. To harden it off place the plant outside in a shady spot for a couple of hours, and repeat for two or three days, increasing its stay outside each day until it’s outdoors most of the day. Then place it under morning sun for a couple of hours and put it in shade for the afternoon. Repeat increasing time under the sun for three or so days until it’s spending most of day and evening outside. I know it seems like a pain, but it’s far better than having your plant keel over from shock and die.
Zucchini is not ready to live outdoors until the soil temperature is reasonably warm, the sources say at least 18-20 degrees Celsius (64-68 F). How the heck would you know what temperature your soil is? Well you can either purchase a soil thermometer – here is one from Lee Valley, or simply leave a comment below if you’re in the Calgary area, and I’ll tell you what the soil in my raised bed is at for a rough reference. To warm up the soil you can use a black plastic mulch which you can get in any garden centre – it’s cheap.
Once it’s ready to go outside (which this year looks like might be July), there is non-proven advice out there. One of my books suggests a floating row cover over the plant if the temperature drops below 18 degrees Celsius (64 F). Since that includes every single night in Calgary, I think it may be more realistic to cover it if the night temperature approaches say 10-15 degrees (which is also sadly every night). Did you know where you can get row covers? Lee Valley among others. I swear I could live there. Or at least have my paychecks redirected there. Point is, zucchini likes warmth, so don’t plant it until there’s at least a resemblance of summer outside.
The planting should be done on a cloudy day or towards the evening to minimize the plants’ stress. Prepare a small bucket of full strength fish and kelp fertilizer before planting. Zucchini is a heavy feeder, so to prepare a spot dig a fairly large hole and mix in some complete organic fertilizer (found at a garden centre or mixed yourself following a recipe here). Mix the fertilizer in so that most of it ends up under the plant. Refill your hole back up with earth, and dig a small hole about two times larger than the root ball of your plant. Ever so gently, trying not to lose any earth, with two spoons if you have to, remove the plant from the container and place it in the hole. If you have a biodegradable container feel free to simply trim off the top lip so it’s below the soil (otherwise it will wick moisture from your plant), slit open the sides with an x-acto knife, remove the bottom and plant the whole thing. From what I understand the reason you want to keep the soil on the root ball is to avoid damaging tiny root hairs that feed the plant. Take some of your pre-mixed fish and kelp fertilizer solution and pour it all around the new plants roots – aiming to mix a slurry that you gently push around the roots as it settles in. Say a little prayer of hope because you just went through some serious labor to get this baby settled.
Zucchinis are notoriously prolific, and should be picked every day should you wish to encourage further fruit production. Pick the fruits when they are four to five inches long for best flavor, but I easily exceed that, and since it’s so fresh, the zucchini still has that sweetness and firmness that young squashes are prized for. Water the plant deeply as needed.
If all that seems like a good deal of finicky work – it is. Which is why many garden guru’s recommend simply waiting for good weather, warm soil and planting right outdoors. And frankly, many people will simply not bother with babysitting plants, just throw seeds down and watch what happens. I think the outline above is a Platonic ideal of zucchini’s life – something that you would take under advisement if your food supply and life depended on it. There’s nothing wrong with either approach depending on your personality and goals, so mix and match the advice above to fit your circumstances.
Otherwise, if you followed the planting directions above, you will soon have one of these:
Which will turn into this:
I’m sure some experienced gardeners would have more to say about growing zucchini in this cold clayey city of ours, so feel free to chime in with your experiences, memories, tips and tricks!