How to plant kale seeds

Wondering how to plant kale seeds? It’s easy when you know what steps need to be taken for successful growth. We’ll cover everything from how-to basics of getting those little green shoots sprouting up through caring for seedlings after they’ve been planted.

How to plant kale seeds

The basics of how to plant kale seeds

Growing kale is a simple way to incorporate some greens into your garden. Growing kale can be a breeze, with it being suitable for both indoor and outdoor cultivation. But before you start, it’s important to understand the basics of planting kale seeds to have a successful crop.

For optimal growth, select a container with good drainage that allows for at least three inches between each seedling. Fill the container with soil up until about two-thirds full, and then sprinkle your seeds evenly over the top of the soil before gently pressing them into place. Once all of your seeds are in place, cover them lightly with more soil before watering thoroughly from above using either a spray bottle or gentle watering can.

If you’re planning on planting outside instead, wait until the soil has thawed and can be easily worked. While kale seeds will germinate in cool soil, they will not germinate in frozen soil. Soil temperatures should be in the range of about 45°-90°F (7°-32°C) for optimal germination.

When ready, dig small holes approximately a 1/2 inch deep into well-draining soil and drop 2-3 kale seeds into each hole before covering them with soil. Water has thoroughly once done sowing all your seeds, and keep an eye out for germination within 10-14 days depending on weather conditions such as temperature.

Once sprouted through their protective shells, care for these newly formed baby plants by making sure they have enough water. The soil should be damp like a wrung-out sponge, and the seedlings should not be sitting in puddles. You can also use a slow-release fertilizer if you like.

How to plant kale seeds indoors for later transplanting

Sowing kale seeds inside is an excellent way to kick off your gardening journey. While you can sow these seeds directly in the garden, it is common for gardeners to start some kale plants indoors when temperatures outside would make for slow germination.

Gather the necessary potting soil, seed trays or pots with drainage holes, fertilizer, water, and kale seeds for planting. You’ll need potting soil, seed trays or pots with drainage holes, fertilizer, water, and the kale seeds themselves. All your supplies should be fresh and clean to avoid introducing common plant diseases. You can soak your kale seeds for a few hours before planting to help with germination if you like, but soaking isn’t strictly necessary.

Start by filling each tray or pot with moist potting soil. Leave at least a half inch of space in the top. Gently press down on the soil so that it is firm but not compacted tightly together. Poke a small hole in the soil surface, about a half-inch deep. Place 2-3 kale seeds in the hole and cover them with a bit of moist potting mix. Water thoroughly yet gently, so as not to disturb the newly-planted seed.

Keep the soil moist while the seeds germinate. You can cover the seedling tray with a clear plastic cover if you like. Water gently until moistened but not soggy – if too much moisture accumulates around your newly planted seedlings, they may become prone to fungal diseases such as damping off or root rot which can quickly kill them off before they even have a chance at growing into healthy plants.

Kale seeds usually germinate and sprout within about a week indoors. You can speed up germination by placing the tray on a seedling mat or heated floor, but once the seeds have sprouted, they like somewhat cooler temperatures. The optimal growing temperature for most brassicas is in the range of about 60°-65°F (16°-18°C).

Also consider reducing the night temperature down to about 50°-55°F (10°-13°C). The growth of certain problematic wilt fungi (such as Fusarium oxysporum f. sp. conglutinans) is slowed at temperatures at or below about 16°C (60°F). And fortunately, kale plants are quite cold-hardy and can still actively grow below 16°C (60°F).

If more than one seed per cell sprouts, trim off the weaker ones so that only the strongest seedling remains in each spot. Optional yet highly recommended, fertilizing each growing seedling with a vegetable-specific fertilizer will provide essential nutrients during the growth cycle and prevent nutrient deficiencies due to poor-quality soil. Adding this extra step will ensure your newly planted seedlings have all they need to thrive.

Sowing kale seeds indoors is a great way to kickstart your veggie garden, yet it necessitates some prepping and attention. Outdoors, the process of planting kale seeds may be slightly different due to climate conditions or soil composition.

How to plant kale seeds

How to plant kale seeds outdoors

Kale is a delectable and healthful green veggie that can be cultivated in your own backyard. Planting kale seeds outdoors straight in the garden soil is an easy process with just a few steps.

The first step to planting kale seeds outdoors is to prepare the soil for the seedlings. The soil should not be frozen and should be free from weeds and other plant debris. Before planting, work some compost or manure into the top 6-8 inches of soil and rake it smooth so there are no large clumps or stones that could impede root growth.

It can also help to take a measurement of the soil temperature with a soil thermometer. Soil temperatures should be in the range of about 45°-90°F (7°-32°C) for the kale seeds to germinate easily.

Next, you’ll need to decide what type of kale you want to grow – frilly leaves or dinosaur? Kale comes from the cabbage family and has been around since ancient times, so it’s relatively easy to grow compared with other vegetables like spinach or collard greens. It also grows quickly – within two weeks after germination, young plants will begin emerging from their seed pods.

Once you have selected your desired variety of kale, spread the seeds evenly over your prepared bed using your hands or a seed tray for precision sowing. Cover them lightly with about 1/4 inch of garden soil. Water gently but thoroughly until all moisture has been absorbed by the ground beneath each seed pod; this will help ensure successful germination and fast growth rates for those tiny little shoots. Use a light layer of mulch such as composted plant matter on top of newly planted seeds as an extra measure against drying out due to hot summer temperatures and sun exposure.

Once sprouts appear above ground (about 7-14 days later), thin out any overly crowded areas by snipping off excess shoots near their base with scissors; this will allow more room for healthy root systems as they continue growing underground during warmer months ahead.

Additionally, if needed provide additional shade protection using row covers during peak afternoon sunlight hours while keeping an eye on water levels – remember: young plants need consistent moisture throughout their life cycle in order to produce abundant yields come harvest time. Finally, once true leaves form on each stem keep weeds away by regularly hoeing around mature plants.

Care for kale after planting

Once you have planted your kale seeds, the care that follows is essential for a successful harvest. Here are some tips on how to care for your kale seeds after planting:

Watering kale seedlings

Kale needs regular watering, but be careful not to overwater, as this can cause root rot or other diseases. Use a very gentle watering can or a garden hose with a water breaker to avoid dislodging the small seeds and seedlings.

Water deeply about once a week in dry weather and more often if there has been no rain. Check the soil with your finger before watering. If it feels damp, then don’t water until it dries out slightly.

Fertilizing seedlings

After seedlings emerge, fertilize every two weeks with an all-purpose liquid fertilizer diluted according to package instructions. You can also top dress the soil with homemade compost for an all-round nutrient boost.

Weeding the garden

Regularly removing weeds is essential to prevent competition with young plants for nutrients and moisture in the soil. Hand weeding is best, as large tools can damage shallow roots when used too close to seedlings.

Prick out tiny weeds as soon as possible so that their roots don’t start to entangle with those of your kale. You can also slice small weeds off at their base with a small, sharp weeding tool like a cobra weeder.

Thinning seedlings

If multiple plants come up in one area, thin them out by snipping off extra stems at ground level using scissors (rather than pulling them up, which could disturb nearby roots of other plants). This will also help prevent overcrowding which can stunt growth and reduce yields later on in the season. Each variety of kale is different, but the plants are usually spaced 6-12 inches apart.

Monitoring for pests

Monitor your kale patch regularly for pests such as aphids or caterpillars which may feed on leaves causing damage or discoloration of foliage over time if left unchecked. Spray these off with a hose periodically during warmer months when they are most active (not during cold spells). Introduce beneficial insects like ladybugs into garden beds to help keep pest populations under control naturally without resorting to chemical treatments that could harm other beneficial organisms living among plants like pollinators or earthworms.

How to plant kale seeds

Common problems when growing kale seedlings

Growing kale seedlings can be a rewarding experience for any gardener. However, it’s important to be aware of some common problems that may arise when growing these plants. Some of the most frequent difficulties associated with growing kale seedlings can include:


Kale is prone to pest infestations such as aphids, caterpillars, and whiteflies. These pests can damage your plants and make them unappealing or even inedible. To keep them away, use natural pest control methods like companion planting with herbs like basil or marigolds and spraying neem oil on the leaves every few weeks.


Kale is also susceptible to various diseases, such as black rot, powdery mildew, and clubroot disease. To prevent these from occurring, ensure your soil has good drainage by adding compost before planting and avoid overcrowding your plants so they have enough space for air circulation between each one. Additionally, water at ground level instead of overhead so moisture doesn’t linger on the leaves, which could lead to fungal growth.

Damping off is a common problem with brassica seedlings like kale. Usually, the stems display the classic damping-off collapse at the soil line, but the plants can also experience yellowed and shriveled leaves (vascular wilt). Fungal pathogens can restrict the flow of water and nutrients into the leaves of seedlings, sometimes leading to seedling death. Move the brassica seedlings to a cooler spot (16°-18°C) with some fresh air/ventilation as soon as they sprout, and even cooler temperatures at night may help keep fungus under control.

Temperature fluctuations can cause significant stress on your kale seedlings, resulting in stunted growth or wilting leaves, ultimately reducing their yield potential. To avoid this, it’s important to keep a close eye on the temperature and make necessary adjustments as soon as possible, whether that be providing additional heat sources or shading depending on what is needed to maintain an optimal range for optimal plant health. Don’t let those pesky temps win the day.

Mary Jane Duford
Mary Jane Duford

Mary Jane Duford is a quintessential Canadian gardener. An engineer by trade, she tends to an ever-expanding collection of plants. In her world, laughter blooms as freely as her flowers, and every plant is raised with a dash of Canadian grit.

Mary Jane is a certified Master Gardener and also holds a Permaculture Design Certificate. She's also a proud mom of three, teaching her little sprouts the crucial difference between a garden friend and foe.

When she's not playing in the dirt, Mary Jane revels in her love for Taylor Swift, Gilmore Girls, ice hockey, and the surprisingly soothing sounds of bluegrass covers of classic hip-hop songs. She invites you to join her garden party, a place where you can share in the joy of growing and where every day is a new opportunity to find the perfect spot for yet another plant.

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