The Root Of Everything: Soils, Amendments & Mulches

Soil really is at the root of everything in the garden. Without healthy soil, plants will not thrive. Period. Whether you are planting in containers or directly into the garden, the use of specific soils, amendments, and mulches will have immediate and lasting benefits! 

Photo by BSIP/UIG/Getty Images

Photo by BSIP/UIG/Getty Images

It's possible to build healthy garden soil naturally through composting and other good practices, but for most of us, that takes a lot of time, skill, and guesswork. And creating proper soil for containers is quite a challenge. Good news: there are a lot of high-quality, bagged soils, amendments, and mulches available to improve your soil, whatever your need or situation might be. Here are a few favorites we offer at Swansons, plus how and when to use them.

Potting Soil & Topsoil

Potting soils are specially formulated for containers. They have been engineered to enhance root development and provide excellent drainage without becoming compacted. Many are formulated for the needs of specific plants, such as vegetables, cacti, and succulents. 

If you are planting in containers - whether indoors or out - be sure to use potting soil. Garden soil is not appropriate for potted plants because it will compact too much, effectively squeezing out the air (which is essential for the plant’s vitality) from the soil. Compost is also not well-suited for container gardening because it is too rich and can burn plant roots. It also tends to hold onto water, resulting in root rot.

Just as garden soils shouldn't be used in containers, potting soils are not the best choice to add to the garden, mainly because most potting soils include perlite. Over time, this lightweight material works its way up to the surface of the soil and may leave an unattractive crust on the garden bed. Additionally, potting soils are not cost effective for filling in large garden spaces. G&B Organics Premium Topsoil, mixed with a soil amendment (see more information below), is great for filling low spots and holes in the garden, lawn or alley.


Swansons-Recommended Potting Soils

For Outdoor Container Projects

G&B Organics Potting Soil
Our most economical potting soil, it is a great choice for most outdoor container gardening. It contains chicken manure, worm castings, and kelp meal, which is especially great when planting nutrient-hungry vegetables in containers. Because the chicken manure may leave a lingering smell, we do not suggest it for indoor use.


For Indoor & Outdoor Container Projects

E.B. Stone Organics “Edna’s Best” Potting Soil
My personal favorite all-purpose potting soil. This is what our floral department uses for repotting and building the beautiful container creations we sell here at Swansons. It has a mild, earthy smell (no manure included), which makes it suitable for indoor as well as outdoor use. When potting soils become dry they can become hydrophobic, meaning they don’t easily absorb water and it takes more time to hydrate the soil. Edna’s Best has combated this issue by adding yucca extract to their soil, which helps the soil rehydrate more easily.


For Extra Drainage

E. B. Stone Cactus Mix
For indoor and outdoor cacti and succulents, as well as other plants that need excellent drainage (such as heathers), we suggest E. B. Stone Cactus Mix. The added sand, pumice, and aged redwood create light and well-draining soil.

Note: For customers that prefer to purchase only one type of potting soil but have an array of plants with different drainage needs, pumice may be added to an all-purpose potting soil to improve drainage.

Both Edna’s Best and G&B Organics potting soils have pH adjusters to give them a pH of 6.5 (slightly acidic).

Photo by amenic181/iStock/Getty Images

Photo by amenic181/iStock/Getty Images

Soil Amendments & Garden Mulch

In most cases, the difference between a soil amendment and a mulch is how you use it. Amendments are worked into the soil and mulch is placed on top of the soil. Some soil amendments (compost, soil conditioner) also make great mulches.

Generally, a soil amendment is used to enrich the soil and to help build soil structure. Many people in the Seattle area have either clay soils or sandy soils. With clay soil, the main concern is compaction. With sandy soil, the major concern is moisture retention. Any of our amendments will help both of these issues!

Mulching is most beneficial. It helps keep weeds in check by covering the soil enough so that sunlight can’t penetrate and weed seeds don't germinate. If new seeds blow in, they will germinate on this nice rich ground surface but removing them will be much easier because of how light and fluffy most mulches are.

Mulch also helps the soil retain moisture and therefore is helpful in keeping your water bill down! The additional loose, nutrient-rich soil allows water to penetrate easily. The soil below the mulch will stay hydrated longer because the mulch is sheltering it from the sun, hence keeping it cooler and slowing evaporation. Approximately two inches of mulch is adequate for the above purposes. 

Note: Soil amendments have nutrients, but not sufficient amounts to forego fertilizers altogether. In fact, amendments, mulches, and fertilizers work best in conjunction with one another. 


Swansons-Recommended Soil Amendments

For Improving Soil Structure Anywhere

G&B Organics Soil Building Conditioner
This product is engineered to deal with issues of compacted or sandy soil.  Larger pieces of bark and recycled forest products help break up compacted soil and create air pockets in the soil, allowing water to better penetrate. This product is also beneficial for sandy soils because organic matter is better at holding onto water, so the soil doesn’t dry out so quickly. We recommend adding conditioner, especially when planting trees, shrubs, and perennials in the garden.

E.B. Stone Organics Planting Compost
This product has a blend of ingredients useful for all soil types: composted wood shavings, redwood compost, mushroom compost, and more. It has a more soil-like texture that the Soil Building Conditioner.


For Vegetable Gardens

Harvest Supreme
If you are planting veggies (and annuals, too) Harvest Supreme is our go-to product. It is very similar to G&B Organics Soil Building Conditioner but has more composted chicken manure, plus rice hulls, bat guano, and kelp meal.

Farmyard Blend
If chicken or cow manure are desired in the amendment, consider Farmyard Blend. Its main ingredients are dairy cow and poultry manures harvested from certified organic farms. It also has rice hulls and recycled forest products, which are both excellent for improving your soil structure.


Before Adding a New Lawn

E.B. Stone Organics Planting Compost
For enriching the soil before sowing or adding sod, we recommend this compost. It will help improve the structure of the lawn while also adding sufficient amounts of fine organic matter. Add about 4 inches of compost and work into the soil 12 inches deep, if possible. If you are unable to work that deeply, add 2 inches of compost for every 6 inches of depth.


For Seeding & Overseeding a Lawn

G&B Organics Soil Building Conditioner
For seeding and overseeding, we recommend using the Soil Building Conditioner. Always follow the instructions on the back label!


Swansons-Recommended Mulch

For Flower Beds

G&B Organics Soil Building Conditioner & E.B. Stone Organics Planting Compost
Mulch preference is largely a question of aesthetics. An excellent and economical option is the Soil Building Conditioner. If you don’t care for the look of the wood chips in the Soil Building Conditioner and prefer a dark, rich-looking soil, then consider the Planting Compost.


For Vegetable Beds

Harvest Supreme
Harvest Supreme is a nutrient-rich mulch to layer over veggie beds. It helps retain moisture in the soil and also slowly adds organic matter and nutrients, with ingredients such as bat guano and kelp meal.

E.B. Stone Organics Planting Compost
A great all-purpose mulch for the garden, this product produces a clean, dark surface covering that helps retain moisture, suppress weeds, and add nutrients to the soil.


Need help on specific garden projects? Ask us on Facebook, Twitter, or Instagram! Just use hashtag #heyswansons and we'll offer advice and inspiration!

Learn more about mulch and compost in these blog posts:

Mulch: We Have So Mulch To Talk About
Compost, And The Soils That Love It