“I built 2 beds measuring 4′ x 16′ and 2 foot deep. I don’t think I need a Black Gold mix for the bottom half. What is something I could [add to] the bottom half of the boxes? Also are Black Gold products meant as a supplement to the soil or a soil replacement?” Question from Kevin of Rome, Georgia
Answer: We have many amendments and soils suitable for raised bed gardening, but we now sell a natural raised bed soil that is specially formulated for your type of garden. Black Gold® Natural & Organic Raised Bed & Potting Mix is just for raised bed gardening, is sold in cost-effective large bales and is OMRI Listed for organic gardening. If you wish to supplement with additional soils or amendments, try the following bulk and/or bagged options.
Quality screened bulk compost, leaf compost, or mushroom compost – These are all rich and fortifying but high in organic matter, which eventually breaks down over time and needs to be replenished.
Quality screened bulk topsoil – Topsoil contains mineral soil as well as organic matter, so not all of its components will break down over time.
Bagged compost, such as Black Gold Garden Compost Blend – This is a good option for smaller-scale raised bed gardening. Treat it as you would bulk compost.
Products sold in bulk are generally available at large landscape supply centers and are sold by the yard. Add topsoil of compost at a ratio of one part topsoil or compost to two parts bagged mix.
Before ordering any soil, be sure you know how much you need by using the soil application formula. Also, be sure to feed your soil with quality fertilizer formulated for vegetable gardening.
Soil Application Formula
To find the amount of soil you will need, determine the volume of your square or rectangular bed by measuring its length, width, and height. Then use the following formula: V = L x W x H.
V = soil volume L = bed length W = bed width H = bed height
So, if your bed happens to be 6 feet x 4 feet x 1.5 feet, multiply 6 x 4 x 1.5 = 36 cubic feet. Our raised bed soil is sold in 2.2 cf bales. To determine the amount of bagged soil you might need (36 cubic feet/2.2 cf bales= 16). If you plan to add topsoil at a 1:3 ratio, then you will need 2/3 mix (24 cubic feet (10.66 2.2 cubic foot bags of raised bed potting mix)) and 1/3 topsoil (12 cubic feet of topsoil). If you want to buy topsoil by the yard, then you must know yardage. Divide the answer in cubic feet by 27 to get the number of cubic yards you might need (36/27= 1.3 cubic yards).
When asked about soil and gardens, the most common question I receive is about how to determine soil pH. Garden professionals emphasize the need to measure soil pH because it can be so important if the soil pH errs towards the extremes–too acid or too alkaline. Soil pH testing is certainly useful when you are getting to know your soil, and it can be managed once identified. It can also help one devise a game plan for what to grow where.
If you want precision soil pH numbers, your best bet is to reach out to your local extension agent for professional testing (click here to learn more), but this can be costly, and precise numbers are not always needed. I recommend this route for gardeners living in areas where soils tend to be more extreme.
For home gardeners living in areas with more average loam soils, it is not necessary to get exact measurements of your soil pH from all the different spaces of your garden. Simple, home-grown tests will help determine if your soil is acidic, alkaline, or neutral. Once you know that, you will know what grows best in your soil, and you can work with it.
The Importance of Soil pH
bigleaf hydrangeas (Hydrangea macrophylla) will bloom blue when they are in soil that is more acidic and pink in more alkaline soil.
pH is designated on a scale from 1 to 14; if you have a pH around 7 your soil is neutral, if your pH is less than 7 it is considered to be acidic, whereas a pH greater than 7 is alkaline. At the far extremes, hydrochloric acid (0 pH) has an extremely low pH, and caustic lye (12 pH) has an extremely high pH. Most plants grow very well in neutral or near-neutral soils, though some plants are specially adapted to more acid or alkaline soils.
For gardeners, soil pH can be an important determinant of what plants will thrive or struggle within a garden. As a general rule, most vegetables and flowers prefer neutral soils. Some plants, like camellia, blueberry, and rhododendrons, prefer more acid soils, while others, like crabapples, lilac, clematis, and sweet peas, tolerate more alkaline soils.
Some plants will grow in a variety of pH levels but show differences in how they grow. For example, bigleaf hydrangeas (Hydrangea macrophylla) will bloom blue when they are in soil that is more acidic and pink in more alkaline soil.
Collecting a Soil Sample
You just need 4 tablespoons of soil to complete these tests.
To test your soil at home, you are going to need to collect a sample. To do this, grab a trowel and dig three or four inches down. Scoop the soil into a bowl, making sure not to contaminate it by touching it. It’s a good idea to collect samples from three to five different areas of your garden to get a good idea of the average pH of the soil you will be working with. Mix them, and then perform the following tests.
Vinegar and Baking Soda DIY pH Test
Knowing your soil’s pH will help you garden better.
(These tests are from the book Garden Alchemy: 80 Recipes and Concoctions for Organic Fertilizers, Plant Elixirs, Potting Mixes, Pest Deterrents, and More (Cool Springs Press, 2020). Reprinted with permission.)
This simple test for soil pH will tell you if you have alkaline, acidic, or neutral soil using household vinegar and baking soda. White vinegar (2.5 pH) is acidic, and sodium bicarbonate or baking soda (8.4 pH) is alkaline. When they are mixed, they fizz. With two samples of soil from the same place in your garden, adding these ingredients will help to determine your soil’s pH type.
Materials
2 small bowls
4 tablespoons soil
Distilled water (do not use tap water as distilled water has a neutral pH)
White vinegar
Baking soda
Test Instructions
Add 2 tablespoons (30 ml) soil to a small bowl and mix it with 1 tablespoon (15 ml) of distilled water.
Add 1 tablespoon (15 ml) white vinegar in and stir. If the mixture fizzes, you have more alkaline soil.
Add 2 tablespoons (30 ml) soil from the same sample to a small bowl and mix it with 1 tablespoon (15 ml) of distilled water.
Add 1 tablespoon (15 ml) of baking soda and stir. If the mixture fizzes, you have more acid soil.
If it does not fizz for either test, you have neutral soil.
Once you know if you have acidic, alkaline, or neutral soil, congratulations! You now know what will grow best in your garden!
Managing Soil PH
Garden lime will reduce soil acidity and add calcium.
Many folks want to take on the job of altering their soil pH if they are largely at one end of the scale or the other. There are various products one can use to manage soil pH. If you have acid soil, you can add liming agents, such as hydrated lime, in addition to more neutral soil amendments, such as Black Gold Earthworm Castings. If your soil is very alkaline, add more acid amendments, such as Black Gold Canadian Sphagnum Peat Moss, as well as acidifying fertilizers, such as elemental sulfur (click here to learn more about acidifying soil). For both liming or acidifying soil agents, be sure to follow the manufacturer’s guidelines for application.
Another practical option for managing soil pH is to only grow native plants that will naturally thrive in your soil, and reserve other plants less adapted to your soil to container gardens or raised beds (click here to learn more about Black Gold® Natural & Organic Raised Bed & Potting Mix). Either way, it always pays to amend your soil with great quality Black Gold Garden Compost Blend. Then celebrate your unique garden soil, and the plants that nature intended you to grow there.
“What is the best fertilizer for a grapevine?” Question from Deb at Lynbrook, New York
Answer: The truth is that grapes don’t require too much fertilizer if the soil is right. In fact, excess fertilization of vines encourages stem and foliar growth and discourages flowering and fruiting. Just picture an established vineyard in Europe. The grapes are old, stunted, and often growing in dry regions, but the oldest, most gnarled vines on the most well-drained soil produce the best wine grapes. Still, a little food is recommended on a yearly basis.
Fertilizing Grapes
Cornell Extension recommends the following fertilization regime with a 10-10-10 fertilizer for grapes in New York State. (Click here for the full document.)
First year – no fertilizer
Second year – 2 ounces
Third year – 4 ounces
Fourth year – 8 ounces
Fifth year & after – 16 ounces
Soil for Grapes
The more crucial factor regarding grape fruiting and success is soil type and drainage. First, most grapes prefer a slightly acid to neutral pH between 5.6 and 7, but some grape varieties also grow well at a slightly higher pH of 7.5. If soil pH is too acid or too alkaline, vines will experience various nutrient deficiencies, which will harm the growth and grape output. If your grapes have leaves that look stressed and unhealthy, I recommend you get a soil test for pH through Cornell Cooperative Extension (click here for more information).
Grapes also grow best in well-drained loam. Amending the soil at planting time with Black Gold® Garden Compost Blend and Canadian Sphagnum peat moss is recommended. Sand is another common amendment that will encourage drainage. Just make sure that your vines are planted where the soil drains quickly.
“I have several raised garden beds (6’x3′ and 2’x2′) both 18+ inches deep for vegetables. I am debating between the “natural and organic potting mix”, “organic flower and vegetable soil”, and “natural and organic raised beds and potting mix”. Is there a clear choice here or would I be good with any?” Question from Lars of Chicago, Illinois
Answer: All three of these products work well for raised bed growing, but our new Black Gold Natural and Organic Raised Bed Potting Mix is specially formulated for raised beds. If I were to choose from the three, it would be my pick. Additionally, I always recommend that gardeners mix a little natural topsoil into their raised beds. The addition of a little natural mineral soil will increase the longevity of the mix. Be sure to supplement with a fertilizer formulated for vegetable plantings.
When determining how the amount of raised bed growing mix to add to your beds, use this formula:
Soil Application Formula
([area to cover] ft2 x [depth in inches desired] x 0.0031 = ___ yd3).
Example: If you wanted to cover a 20 square foot area with 2 inches of compost, the result would be: 20 ft2 x 2 inches of compost x 0.0031 = 2.48 yd3.
“Why aren’t my roses growing? My rose bushes do not grow, and I fertilize them once a month, but they don’t grow. Soil is clay-like. They are semi-shade, I have a lot of big trees. They do flower. What else can I do?” Question from April of Dresden, Tennesee
Answer: There are three key factors that are likely keeping your roses from growing, thriving, and flowering to their fullest. They are:
Sunlight: Roses need full sun to grow and flower at their fullest. Six hours per day is the bare minimum they need to really perform well. Eight to twelve hours is even better. The morning sun is preferable to dry leaves early in the day, which dissuades fungal diseases.
Soil: Roses require a fertile, well-drained soil that is slightly acidic (pH 6.5-7) and high in organic matter to perform at their fullest. Amend the soil where they are planted to encourage better root growth and performance. Black Gold Garden Soil and Black Gold Canadian Sphagnum Peat Moss are two excellent amendments to consider
Competition: Tree roots quickly drain water and nutrients from the soil. It is wise to plant roses away from tree roots to avoid competition.
Please watch the video below to learn more about growing roses organically.
Miniature weeping pussywillows can be grown in pots or gardens and stay quite compact.
“I bought a Salix caprea ‘Pendula’ (or a miniature weeping pussywillow) on March 20th. I was wondering if the Black Gold All Purpose Potting Mix would work to transplant the tree in? I am repotting it into a larger container. I am also wondering how large of a container I may need. Thank you!” Question from Sloan of Knoxville, Tennesee
Answer: The maximum size that your miniature willow (Salix caprea ‘Pendula’) should reach is 6 feet, though they have been known to get larger. The container you choose is just as important as the potting mix you supply to the tree.
Planting Miniature Weeping Pussywillows
Willows are moisture-loving trees that develop extensive root systems, so you must choose a large, strong container if you want a happy, potted specimen. Choose a container that is at least DIA 34″ H 29″ (or deeper), weather-proof, and fitted with drainage holes at the bottom. The pot should have a bottom saucer to catch water. The right pot may be costly, but it will provide a good, longterm home for your tree.
Planting in a plain potting mix would be a mistake. Potting mix breaks down over time, so it needs to be replenished every few years or so. Instead, select a soil mixture with more permanence. Mix natural topsoil with organic components, such as Black Gold Garden Compost Blend, and water-holding Black Gold Natural & Organic Ultra Coir, which are both OMRI Listed for organic gardening. A good combination would be one part topsoil to one part compost and one part coir potting mix. Be sure to combine the ingredients evenly. If you can skim off topsoil from your own yard, that would be most cost-effective.
Willows require regular water to survive in containers, so you may want to install drip irrigation to help keep the container moist on hot summer days.
“We will be planting roses on the north side of the house this summer. We have clay soil. What do you recommend mixing into the soil?” question from Roseanne of Rockford, Illinois
Answer: Roses grow and resist disease best when grown in full sun. The north side of your home may not be the best spot for roses unless you plant them far enough from the foundation to get enough full sun. Hydrangeas, fothergilla, glossy abelia, summersweet, and sweetspire are better flowering foundation shrubs for the north side of a home. I recommend that you calculate what garden areas along that side of your home get at least six hours of sun per day. (Eight hours is better.) Roses won’t perform well with less.
When it comes to the soil for roses, good drainage and good fertility are essential. If your soil is heavy clay, it will require lots of amendments to get it in shape for roses. Please read the following articles to learn how.
Roses prefer soil with a slightly acid pH of 6.5, so peat moss is a recommended amendment. You also have the option of building your soils up and berming along your foundation to lift your soils to facilitate better drainage. We also suggest that you fortify your newly planted roses with alfalfa meal (3-1-2), a natural fertilizer that’s great for roses.
I also encourage you to watch the video below about growing roses organically.
When it comes to a good potting mix for succulents, fast drainage is essential. A good succulent mix must drain very well but also have some organic matter. Black Gold Cactus Mix has the perfect balance of good drainage and organic matter. When choosing a pot, pick one that is several inches larger than the last and has drainage holes at the bottom as well as a saucer to catch water.
Once your succulents are newly planted, it is smart to top the soil with decorative gravel to keep the surface dry and attractive. Pebbles and gravel for terrariums come in different sizes, textures, and colors. Those in light shades let plants stand out without overstatement.
Cultivate a shower of flowers for the holidays! Christmas cactus and Thanksgiving cactus are easy to grow if you know what you are doing. Get yours to grow and bloom to its fullest year after year. Here are the seasonal steps that you will need to know for the most beautiful display!
“In a raised bed application, what should I use first before adding soil to prep the bed to reduce weeds and grass?” Question from Marlene or Stuart, Florida
Answer: There are several ways to stop perennial weeds from rising from the base of a new raised bed. You can either do the obvious– roll up your sleeves and completely desod and remove all weeds from the base of the bed–or you can place an organic cover at the base that will break down over time. If you choose to desod, you may also consider double digging below your beds to encourage deep rooting. (Click here to learn more about double digging.)
Raised Bed Organic Covers
The three organic covers that I recommend include either a layer of plain cardboard, black-and-white newspaper, or biodegradable burlap garden cloth. Any of these will work well if you provide full coverage. Place the cover of your choice at the base of the beds to stop weed growth, and then add enriched, raised-bed soil.
Raised Bed Soil Preparation
Raised bed soil should contain a mix of your own topsoil amended with lots of organic matter. Black Gold Garden Compost Blend, Black Gold Earthworm Castings, and an organic soilless potting mix, such as Black Gold Natural and Organic Potting Mix, are all good choices. Soil-to-amendment ratios depend on topsoil quality; good topsoil requires fewer amendments. In general, mix two parts topsoil to one part compost and one part soilless potting mix or earthworm castings. If drought is a problem in your area, add a 2- to 3-inch layer of compost along the soil surface to reduce surface water loss. I also recommend that you fortify your soil with a quality vegetable fertilizer.
To stop further weed encroachment, remove the grass from around your raised beds. Surrounding the beds with walkways covered with pebbles or organic mulches will look great and really help with weeds! (Click here to learn more about mulch solutions.)
Answer: We have many amendments and soils suitable for raised bed gardening, but we now sell a natural raised bed soil that is specially formulated for your type of garden. Black Gold® Natural & Organic Raised Bed & Potting Mix is just for raised bed gardening, is sold in cost-effective large bales and is OMRI Listed for organic gardening. If you wish to supplement with additional soils or amendments, try the following bulk and/or bagged options.
