How Much Soil Do You Need for a 10 Gallon Grow Bag?

Grow bags are a great option for container gardening. They allow you to grow plants vegetables and herbs in a lightweight, portable fabric bag. 10 gallon grow bags are a popular size, providing enough room for small trees, bushes, or a decent harvest of vegetables.

But how much soil do you actually need to fill a 10 gallon grow bag? This handy guide will walk you through the soil volume required and provide tips to ensure your plants thrive in their fabric home

Calculating Soil Volume for a 10 Gallon Grow Bag

The key measurement needed is the total volume of your 10 gallon grow bag. Volume is calculated by multiplying the length x width x height of the container.

A typical 10 gallon grow bag has the following dimensions:

• Length: 15 inches
• Width: 15 inches
• Height: 13 inches

So the math works out as:

• 15 x 15 x 13 = 2,925 cubic inches

To convert to cubic feet, divide by 1,728 (the number of cubic inches in a cubic foot).

• 2,925 cubic inches / 1,728 = 1.5 cubic feet

Therefore, a standard 10 gallon grow bag holds approximately 1.5 cubic feet of soil.

For a visual reference, 1.5 cubic feet of soil will fill about 2-3 regular sized wheelbarrows.

Allow for Settling When Filling Your Grow Bag

When first filling your grow bag, it’s important to account for soil settling. As the bag sits over time, the soil particles will compact down, reducing the overall volume.

To prevent your grow bag from ending up partly empty, add an extra 10-20% more soil than the calculated volume.

For a 10 gallon grow bag:

• Add 1.5 cubic feet (calculated volume)
• Plus 10-20% more (0.2 – 0.3 cubic feet)
• Total soil needed: 1.7 – 1.8 cubic feet

This overage will ensure the bag remains full after the inevitable settling process.

Use High Quality Potting Soil for Grow Bags

Don’t just grab any old soil to fill your grow bag! For optimal drainage and aeration, use a high quality potting mix specifically formulated for containers.

Here are some things to look for in potting soil:

• A blend of peat moss, compost, vermiculite or perlite
• Lightweight and fluffy texture
• No heavy clays or dense garden soil
• Balanced pH between 6.0 – 6.5
• Slow release fertilizers mixed in

Avoid soils with water retaining additives like sponges or gels. These can lead to overly soggy conditions in fabric grow bags.

You can further improve drainage by mixing in 10-20% perlite or pumice. Or add compost for extra nutrients.

Allow Space at the Top for Watering

When filling your 10 gallon grow bag, don’t pack the soil all the way to the top edge. Leave 2-3 inches of headspace for:

• Watering – allows space for water to penetrate without overflowing the sides
• Mulching – headspace provides a spot to add mulch, compost, or other toppings
• Root growth – roots will expand up into the headspace seeking air and water

This gap will prevent messy soil and water spills from your grow bag.

Filling 10 Gallon Grow Bags in Easy Steps

Now let’s go through the complete process for properly filling a 10 gallon grow bag with soil:

1. Assemble Your Supplies

• 10 gallon grow bag
• 1.7 – 1.8 cubic feet of potting soil (with extra for settling)
• Scoop, bucket, or wheelbarrow for moving soil
• Watering can or hose
• (Optional) Amendments like perlite, compost, etc

2. Add a Layer of Screening (Optional)

To prevent soil from leaching out drainage holes, cut landscape screening to size and line the bottom of the bag.

3. Mix In Any Amendments

If you want to amend with compost, perlite, etc, thoroughly mix it in with your potting soil before filling the grow bag.

4. Fill Bag 2/3 Full

Scoop soil into the grow bag, filling it about 2/3 of the way full. Gently pat down with hands.

5. Water Thoroughly

Water the soil until it’s completely saturated and excess starts running out the drainage holes. This will settle soil into place.

6. Let Sit Overnight

Allow the wet soil to settle overnight before finishing the filling process.

7. Top Off with Remaining Soil

The next day, fill grow bag with remaining soil, leaving 2-3 inches of headspace. Lightly compress again.

8. Water Again & Check for Settling

Water thoroughly a second time. Check next day – if soil level has dropped, add more.

And there you have it – a properly filled 10 gallon grow bag ready for plants!

Ideal Plants for 10 Gallon Grow Bags

Here are some great options for plants that will thrive planted in a 10 gallon grow bag:

Herbs & Vegetables:

• Bush tomatoes – try determinant varieties
• Peppers – good for 1-2 pepper plants
• Eggplant – look for compact varieties
• Herbs – rosemary, thyme, sage, oregano, etc
• Leafy greens – kale, chard, lettuces
• Radishes, beets, carrots – perfect for shallow rooted veggies

Fruits:

• Dwarf fruit trees – select self-pollinating varieties like apples, peaches, plums
• Blueberry bushes – plant 1 bush per bag
• Strawberries – can fit 5-10 plants in a 10 gallon bag

Ornamentals:

• Miniature roses – allow room for just 1 rose bush
• Hydrangeas – opt for dwarf varieties like ‘Little Lime’
• Lavender – 1-2 plants works well

Key Takeaways

• For a standard 10 gallon grow bag, you need approximately 1.5 cubic feet of soil
• Add 10-20% extra soil to account for settling
• Use light, fluffy potting mix, not dense garden soil
• Leave 2-3 inches of headspace, don’t fill to the brim
• Water thoroughly after filling to settle soil
• Herbs, vegetables, small fruits, and ornamentals all grow well in 10 gallon bags

With the right amount of high quality soil and a properly filled bag, your plants will have the ideal foundation to develop strong root systems and achieve abundant growth. Happy gardening!