Hands mixing potting medium

How to Make Soilless Potting Mix

Hands mixing potting medium

Purchase a pre-made soilless potting mix or mix your own growing medium. Image from UW Garden Guide.

Flowers springing merrily from dirt-filled pots and planters is a sight that we take for granted. After all, aren’t plants supposed to thrive in dirt? The truth is, planting in containers requires a little more finesse, since you’ve got to encourage the medium to hold moisture against the plant’s roots while draining away any standing water to prevent drowning them.

It’s lucky for us, then, that agricultural scientists realized that by using soilless potting mix, both goals can be accomplished simultaneously, while still creating a sterile growing environment for plants that might be susceptible to soil-borne diseases.

What is Soilless Growing Medium?

Soil less growing media is exactly what it sounds like: a material designed for growing plants that contains no garden soil, sand or clay. Soilless potting mixes have a light texture, creating an ideal environment for seeds to germinate and roots to penetrate deeply without obstacles. It’s important that plants in containers are able to gather nutrients as efficiently as possible because they can’t spread far.

Creating the best soilless mix is the aim of many home gardeners, who start with a basic soilless mix recipe and make subtle changes until it meets their needs. Most recipes have a few common ingredients: a material to hold water, another to prevent compaction and something to provide fertility. When these elements come together properly, the end result is a mix with a near-neutral pH to ensure the optimal utilization of nutrients in the plants you grow.

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Worm Castings in Soilless Mixes

Researchers experimented extensively with worm castings and their effects on plants in the 1980s, and came to a few conclusions:

  • Worm castings contain similar nutrients to other organic fertilizers, but because of the biology of the worms, the nutrients are in forms more useful to plants. Other organic fertilizers rely on microbes to break them into useable forms – it takes time to acquire these tiny helpers in sterilized medium.
  • Vermicompost (worm castings with some worm bedding left behind) encourages faster germination of seeds than commercial growing media. Plants in their tests also grew bigger in vermicompost-based mixes.
  • Mixing vermicompost, which tends to have a high pH, with peat, which tends to have a low pH, creates a medium with a naturally neutral pH. A medium with this combination of materials does not usually need the pH artificially adjusted, simplifying the work of the container gardener.

For these reasons, we recommend adding worm castings to soilless growing mixes.

Soilless Mix Recipes

A basic, but effective soilless potting mix starts with peat, perlite and an organic fertilizer, such as worm castings. For transplants, mixing one part peat, one part worm castings and one part perlite, by volume, creates a suitable medium. Seed-starting mixes should contain half as much perlite to help seedlings maintain a slightly higher humidity level. Adding about a half-ounce of Epson salts per cubic foot of either mix will create a complete nutrient profile.

Worm casting fertilizer from Hooks & Lattice will turn your soilless potting mix recipe on its ear, adding a fertilizer that can last all year while helping to maintain proper moisture for your plants. Available in both five and 10-pound bags, our worm casting fertilizer is ready for any size container garden.

Two window boxes on a home with flowers and ivy

The Best Trailing Plants for Hanging Baskets & Window Boxes

Window boxes and hanging baskets allow you to add color to otherwise drab areas of your landscape. Properly designing these outdoor accessories requires the right combination of plants. Most baskets and boxes contain a mix of medium, short, and trailing plants that work together to create multiple layers of texture and interest. The taller plants are often the most noticeable, while the trailing plants are pulled from the more utilitarian ranks of ground covers and vines. Here are some of our favorites.

Trailing Plants for Hanging Baskets

Three hanging baskets with bacopa, sweet potato vine, and calibrachoa

These trailing plants are popular in hanging baskets: bacopa, sweet potato vine, and calibrachoa. Photos from tamu.edu.

Hanging baskets look great with plants that create thick canopies. The most popular trailing plants for hanging baskets produce an abundance of vibrant blooms. They can turn hanging planters into huge, colorful clusters of flowers suspended in mid-air.

Hanging baskets are difficult to maintain for more than a single season, so in many areas, gardeners prefer annuals so they don’t have to worry about their flower baskets in the winter.

Annual Varieties Well-Suited to Hanging Baskets
Common Name Scientific Name
Cascadia Hybrid Snapdragon Antirrhinum pendula
Bonfire Begonia Begonia boliviensis
MiniFamous Calibrachoa Calibrachoa spp.
Cora Cascade Vinca Catharanthus roseus
Spreading Sunpatiens Impatient Impatiens x hybrida
Blue Mountain Nierembergia Nierembergia hippomanica
Avalanche, Wave, and Tidal Wave Petunia Petunia x hybrida
Boutique Blue Bacopa Sutera cordata
Whirlybird Nasturtium Tropaeolum majus
Sweet Potato Vine Ipomoea batatas

Trailing Plants for Window Boxes

Two window boxes on a home with flowers and ivy

English ivy (hedera helix) can be grown as an perennial in much of the United States. Its vines add a lovely trailing accent to window boxes.

Whether you mount them under windows or hang them from deck railings, flower boxes look great with vines spilling over the sides. Many gardeners choose trailing plants with flowers, but others prefer vibrant green leaves.

Any plants that do well in hanging baskets will thrive in window boxes, but may need to be replanted each year. Because they can hold significantly more growing medium than hanging baskets, window boxes can also support much larger, perennial plants to create container gardens that return year after year. When choosing plants for perennial window boxes, make sure that you group species with similar watering needs that do well in your USDA Hardiness Zone.

Perennial Varieties Well-Suited to Window Boxes
Common Name Scientific Name USDA Hardiness
Alyssum Alyssum spp. Zones 3 to 8
Hardy Iceplant Delosperma floribunda Zones 5 to 8
Clove Drops Diantdus caryophyllus Zones 5 to 9
Ornamental Strawberries Fragaria x ananassa Zones 4 to 8
Coral Bells Heucherella spp. Zones 4 to 9
Lantana Latana spp. Zones 8 to 10
Periwinkle Vinca minor Zones 4 to 9
English Ivy Hedera helix Zones 5 to 9

Vines for Containers

Don’t forget plants that grow up instead of hanging down! Some vines can be grown in planters and trained up a trellis or allowed to fall to the ground. Vines with shorter stems tend to do best, but longer vines can be clipped to the container’s rim once they reach a desired length to create a draped effect. Vines grow aggressively, so be sure to provide plenty of water and fertilizer during their incredible growth spurts.

Vines Well-Suited to Containers
Common Name Scientific Name
Glory Vine Eccremocarpus scaber
Morning Glory Ipomoea purpurea
Creeping Gloxinia Lophospermum spp.
Runner Beans Phaseolus spp.
Black-eyed Susan Vine Thunbergia alata
Two coco coir lined hanging baskets on a pole

What is Coconut Coir?

Coco fibers

Coco coir is made from the fibers of coconut husks.

Once piled into landfills and forgotten, coconut coir has found a new purpose in the garden. Coco coir can be found lining hanging baskets and window boxes, and appearing as an ingredient in many plant growing mediums. Coconut coir brings several useful characteristics to the table. It’s also a completely sustainable and environmentally friendly material. But what is it, exactly?

In a coconut processing plant, coconuts arrive covered in a course, brown, hairy material that surrounds the husk of the coconut. This is the coir. Until recently, it was frequently discarded as a waste byproduct of coconut processing. Today, though, the coconut coir gets a new life after being sorted by the length of the coir fiber. The longer, thicker fibers go to make mats and liners for planters and hanging baskets, while the shorter ones are chopped up and pressed into preformed liners and biodegradable pots.

A pile of coconut husks

Leftover coconut husks are processed into a variety of products, including coir liners.


Coconut Coir is a Green Material

Coconut coir is eco-friendly for lots of reasons. Also sold as “coco coir” or “coco fiber,” it requires little additional processing, is abundantly available, and keeps trash out of landfills.

Compare that to a similar material, peat. Peat has long been used to line wire hanging baskets, but in recent years, it has become controversial because it’s harvested from peat bogs that have taken centuries to mature. Although restoration of harvested peat lands has been attempted, Washington State University researchers report that during the first several years after restoration, peat lands release extremely high levels of carbon dioxide, adding greenhouse gases to the atmosphere. While peat is a natural material like coco coir, it may not be the most environmentally friendly option for your garden.

Two coco coir lined hanging baskets on a pole

Line a hanging basket with coco coir to retain water in the soil.


Coco Coir Liners Make Gardening Easier

Container gardening can be challenging, and one of the biggest problems is keeping the soil moist. Potted plants can dry out much more quickly than plants in the ground. By adding a coconut coir liner to your window boxes or hayrack planters, you can help slow dangerous drying, since a coco liner can absorb about seven times its own weight in water. Over time, the liner will deal this water back to the soil. This helps plants stay hydrated without the disease risks associated with over-watering, such as fungus, bacteria, and harmful root rot.

The water-retaining qualities of coco fiber are particularly valuable in hanging baskets. Exposure to drying winds often removes water from the soil and dries out the plants. Since coconut coir deals out water to the roots as needed, you have a little more room for error if you forget to water your baskets. Unlike a plastic liner, a coco coir hanging basket liner permits plenty of air penetration to roots, allowing you to plant your basket annuals much closer together than would be possible in a pot.

Coconut coir liners are also incredibly durable and can be reused for many years if carefully handled. As they slowly break down, they will not change the pH of your soil significantly, since they have a natural pH of 5.5 to 6.8. What they will contribute over time, though, are lots of nutrients to your container soil, including the macronutrient potassium, as well as micronutrients iron, manganese, zinc and copper. Potassium is vital to bud formation in flowering plants; micronutrients contribute to plant health in numerous ways.

Coconut liners are a sustainable gardening material that will help protect the plants in your window boxes and hanging baskets from the heat of the summer. Check out the wide range of coco fiber products available at Hooks & Lattice before planting this season.

When and How to Start Seeds Indoors

Tools for starting seeds inside

Starting seeds indoors is a great way to get a jump on spring gardening.

Need to beat cabin fever while snow still clings to the windowsills and frost hangs heavy in the air? There’s no better way to do it than coaxing a pack of seeds into germinating indoors. Starting plants indoors may be one of the best things you can do for your garden. Not only does seed starting allow you to choose from a much wider range of plants, but you will also know that your mature plants are healthy since you raised them from wee little seedlings.

What Materials Do You Need to Start Seeds Indoors?

Veteran gardeners know the secrets of starting seeds indoors, but if you’re at the beginning of your gardening adventure, you probably have a lot of questions. Knowing how to start seeds indoors saves the sometimes considerable costs associated with using transplants for annual flower, herb or vegetable gardens year after year. With your shiny, new seed packets in hand, you should go about collecting the necessary supplies for seed starting.

Many gardeners use inexpensive, prefabricated tabletop greenhouse kits for starting their seeds. These units are available at home improvement stores and through garden catalogs. These miniature greenhouses provide casual gardeners with almost everything they need to start a few plants with very little experience. They generally come with compressed peat pellets with a dimple in the center to place your seed. As you water them, they expand impressively to form net-wrapped wads of growing medium, which are easy to transplant when the time comes.

Gardeners who start many seedlings year after year may find these units limiting, though. For a DIY option, you can make your own biodegradable pots from newspaper, fill them with a peat-based seed starting medium, and put them into large clear plastic sweater boxes. Some home gardeners use an egg carton and put the soil and seeds inside cracked eggshells. You can also simply sow the seeds directly in a window box liner or planter liner, which can easily be moved outside when the plants are ready. No matter what you choose to start your seedlings in, you’ll need to add artificial fluorescent lighting, but a CFL bulb in a lamp may be enough for a few seeds.

Egg carton and egg shells with young plants

Do-it-yourself seed starting in eggshells! Image from Hew and Sew.


How to Plant Seeds Indoors

Every seed needs to be handled a little differently. Your seed packets will explain how deep to plant the seeds and if any special treatment is required prior to planting. Small seeds are generally just sprinkled across the top of pre-moistened seed starting mix, but bigger seeds, like watermelons or pumpkins, may benefit from deeper planting. There are some oddball seeds out there, but for the most part the bigger the seed, the deeper it needs to go. Before you poke them into their individual cells or pots, check your seeds carefully to ensure they’re clean and free of any fuzzy surface molds that might cause them to fail.

Once you’ve given your seeds the all-clear, water them just enough to keep the growing medium from drying out, sit back and watch carefully for the new seedlings to emerge. Some seeds take longer than others to germinate, so be patient with your indoor seed starting. If they go more than about a week past their ideal germination window, though, it may be time to try again with fresh seeds. Sometimes seeds are just bad.

Black plastic window liners

Consider starting your seeds in window box liners. When they’re ready, just carry the liner outside to your flower boxes!


When Should You Start Indoor Seeds?

To get your planting time right, you’ll need to figure out the average last frost date for your region. Almanac.com has an overview of major U.S. cities, and Dave’s Garden lets you look it up by zip code. Determine when the danger of frost has passed and then count backwards to find the date for starting your seeds.

The chart below shows the germination and transplant times for some common garden flowers, herbs, and vegetables. Specific information can be found on your seed packets, too. Plan the timing carefully, because you don’t want to put out seedlings that are too young to survive, nor do you want to move leggy transplants out to the garden.

Starting seeds indoors can be incredibly rewarding, especially when your flowers, herbs or vegetables are destined for a durable, long lasting planter from Hooks & Lattice. As soon as those little plants pop their heads out from the soil, it’ll feel like spring has already sprung! Have you successfully started seeds indoors and transplanted them outside? Tell us about it in the comments!

Common Name Days to Germination Weeks to Transplant
Aster 8 to 10 days 7 to 8 weeks
Coleus 8 to 10 days 9 to 10 weeks
Dianthus 5 to 7 days 12 to 14 weeks
Impatiens 15 to 18 days 10 to 11 weeks
Marigold 5 to 7 days 12 to 14 weeks
Pansy 6 to 10 days 14 to 15 weeks
Snapdragon 7 to 12 days 15 to 16 weeks
Vinca 10 to 15 days 14 to 15 weeks
Zinnia 5 to 7 days 8 to 9 weeks
Basil 5 to 15 days 6 to 8 weeks
Chives 10 to 14 days 6 to 8 weeks
Cilantro 10 to 15 days 6 to 8 weeks
Dill 21 to 25 days 4 to 6 weeks
Lavender 15 to 20 days 6 to 8 weeks
Oregano 10 to 15 days 6 to 8 weeks
Parsley 15 to 30 days 8 weeks
Peppermint 15 to 30 days 6 to 8 weeks
Sage 10 to 21 days 6 to 8 weeks
Thyme 5 to 20 days 6 to 8 weeks
Fruits & Vegetables
Broccoli 5 to 10 days 6 to 8 weeks
Cucumber 7 days 3 to 5 weeks
Lettuce 5 to 10 days 6 to 8 weeks
Okra 7 to 14 days 4 to 6 weeks
Pepper 7 to 14 days 6 to 8 weeks
Pumpkin 7 days 4 to 6 weeks
Tomato 7 to 14 days 6 to 8 weeks
Watermelon 7 days 3 to 5 weeks