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How and when to use seed starter kits


Most home gardeners use seed starter kits in early spring or late winter. However, if you’re planning a fall garden or are planting later than usual, summer is also a good time to get started. Not every plant can tolerate the heat well, though, so you need the right seed starter kit to ensure the seeds germinate, grow and thrive.

Benefits of planting in summer

There are many benefits to using a seed starter kit in the summer.

  • Variety: These kits offer it, ranging from herbs to flowers to certain vegetables. If you’re trying to find specific plants at the nursery in summer, you might find yourself limited in selection. But when planting from seed, you can get nearly anything you want to grow at any time.
  • Price: Seed kits are generally cheaper than live plants. This is partly because seeds don’t take up much space and the nursery doesn’t have to deal with the upkeep. Seed starter kits also include multiple seeds which, if stored in a dry cool environment, can last 5 to 10 years. This gives them a lower cost per seed or potential plant.
  • Timing: Planting in summer lets you get started sooner, especially if you sow the seeds indoors in a controlled environment. This has other advantages, too, since it lets you keep seedlings or young plants away from pests, the elements, extreme temperatures and plant disease.
  • Monitoring: Growing seeds indoors makes it easier to monitor the nutrients and other resources they receive. This lets you ensure they develop a strong root system and can survive when transplanted to the garden. And, since you’ve started them in summer, you can extend the growing season rather than having to wait until fall.

You need to pick the right seed kit for your climate, soil and environment. Otherwise, they won’t grow as intended or will die in the summer heat.

What’s included in a summer seed starter kit


Although some seed starter kits for summer include seeds, many do not. Because of this, you’ll need to purchase them separately. Doing so gives you the opportunity to choose exactly what you want to grow.


Kits typically include containers. You can find them with square, round or hexagonal compartments for seedlings. Some feature around a dozen compartments, while others have anywhere from 50 to 100. Others are not divided at all, meaning you can plant the seeds together.

Depending on the kit, you can get either long trays or separate deep inserts for individual seeds. Some container kits are biodegradable, while others are meant for more permanent use. There are also those that hold young plants until they’ve established a strong enough root system to be transplanted outdoors.

Some kits come with peat pellets or pots for you to sow seeds into. They’re biodegradable, meaning you can plant them directly outside when the seedling is big enough. Even with these, you still need fertilized soil for indoor and outdoor plants.

Choose the container or tray based on the plants you’re growing. For larger plants, such as tomatoes or squash, look for ones with compartments that are at least 2 by 2 inches. For smaller ones, such as cabbage or herbs, pick compartments that are around 1.5 by 2 inches.


Kits also feature clear plastic, domelike lids. These either snap into place or sit on top of the container. Lids help keep moisture in without blocking the light, so they’re necessary for most seedlings.

Base tray

Kits usually include a base tray that sits under the main container and collects excess water. If you’re using a warming mat to speed up germination, make sure the tray is resistant to heat. Get one that’s also well-balanced so the water doesn’t accumulate in one location.

Growing medium

Larger kits sometimes include a growing medium such as potting soil, coconut coir or peat pellets. Smaller ones usually require you to purchase the medium separately. If the medium is included, it will be fertilized or enriched with the nutrients needed to make the seeds grow.

Best seeds for summer planting

You can grow many types of heirloom vegetables, flowers and herbs in a seed starter kit. But if you’re looking for ones to grow from summer to fall, here are the best options.

  • Tomatoes
  • Radishes
  • Spinach, lettuce, chard and other leafy greens
  • Hot peppers
  • Celery
  • Cucumbers
  • Broccoli
  • Green beans
  • Brussels sprouts
  • Wildflowers
  • Daisies
  • Perennials
  • Petunias
  • Pansies
  • Cilantro
  • Basil
  • Thyme
  • Parsley

Consider getting a variety pack of herb seeds or vegetable seed variety pack. That way, you can grow multiple things at once and get the most from your summer planting.

When to avoid using a seed starter kit

Don’t use a seed starter kit for plants with fragile roots unless the container is biodegradable or you intend to keep them in the original container. When growing root vegetables or beans, sow them directly into the ground.

Tips on using seed starter kits in summer

  • Plant hardier plants or summer vegetables outside: This includes tomatoes, peppers and some herbs. Sow the seeds into the garden, but keep them away from direct sunlight.
  • Use the lid as needed: The lid is useful for creating a controlled environment for seeds, but should be removed if the internal temperature is too hot for them to germinate. Also, remove it if the seedlings are starting to press up against it.
  • Follow the directions on the seed packets: All plants have optimal growing conditions, so read the back of each seed packet before planting.

What you need to buy for seed starter kits in summer

Jiffy J410 Seed Starter Kit

Jiffy J410 Seed Starter Kit

This basic starter kit features a complete plastic greenhouse and 10 starter pellets for vegetables, flowers or herbs.

Sold by Amazon

Plantonix Coco Bliss Premium Coconut Coir Pith

Plantonix Coco Bliss Premium Coconut Coir Pith

This 10-pound brick of organic coconut coir is perfect for outdoor planting in sandy or warm soil. It’s also great for growing seeds indoors, as it helps them develop a strong root system and absorb nutrients.

Sold by Amazon

Lostronaut Long Stem Compost Soil Thermometer

Lostronaut Long Stem Compost Soil Thermometer

At 16 inches long, this thermometer is the perfect way to check soil’s temperature to ensure it’s ideal for your plants. The thermometer is durable, easy to read and comes with a carrying case.

Sold by Amazon

Yskea Seed Starter Tray with Light

Yskea Seed Starter Tray with Light

If you’re looking for a complete seed starter kit, this one’s for you. Great for flowers, vegetables, fruit and other plant varieties. A convenient, compact way to grow seedlings. Comes with plant growth light humidity dome.

Sold by Amazon

Miracle-Gro Moisture Control Potting Mix

Miracle-Gro Moisture Control Potting Mix

Meant for indoor and outdoor use, this potting mix contains all the necessary nutrients to ensure vegetable and flower seeds germinate and thrive.

Sold by Amazon

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