Getting the soil right for palm trees is a critical component for optimum growth. Use soil with insufficient nutrients and the palm won’t grow.
Most palm growers, and even nurseries selling container-grown palm trees, will advise on the soil being well-draining.
That’s certainly true.
But it also needs to account for the soil pH, macronutrients, and retain all the nutrients in the soil without needing to over-fertilize to fulfill the nourishment needs of palm trees.
Unfortunately, that often means you need to make your own soil mix.
With that in mind…
What is the Best Soil for Palm Trees?
Sandy loam is the best type of garden soil to plant an outdoor palm tree in. Potted palms need to use a potting mix that is well-draining and provides sufficient nutrients. Perlite and peat moss are extremely light soils providing the drainage requirements palms need. Topsoil and sand will need to be added to lightweight soils, as well as additional soil amendments which vary by the growing climate. Typically, amendments for soils that palm trees need include topsoil, bark, wood chippings, sand, and dolomite. For planting outdoors, garden soil shouldn’t have more than 20% of the ground soil be amendments. If higher amounts of amendments are needed, mounding the soil is the better planting method.
The Soil Requirements for Planting Palm Trees Outdoors
A good ground soil for palm trees will provide a stable base and drain really well. Ideally, at a rate of one inch per hour.
To test your soil, you can dig a hole that’s 12 inches wide and 12 inches deep, fill it with water, let it drain, then repeat and time it the second time you water it.
More than an inch of drainage within an hour indicates the site is too dry, in which case adding organic materials will retain moisture for longer.
When the soil loses less than one inch of moisture per hour, it needs the drainage improved.
For that, use soil amendments like perlite, peat moss, sand, or vermiculite.
Soil Acidity for Palm Trees
Palm trees tend to favor soil that’s slightly acidic.
They can do well in soils with a pH ranging from 5.5 to 7.5. However, the ideal conditions are between those ranges at around a pH of 6.3.
Soil acidity test strips are the quickest way to test your soil acidity.
The more organic soil amendments you use, the higher the soil acidity.
When the soil is too acidic (under 6.3 for palm trees), dolomite limestone is effective at increasing pH levels.
Quality dolomite usually as provides up to 12% magnesium and much as 22% calcium, both of which are essential macronutrients for palm trees.
Amendments for Nutrient Retention in Soil
The bane of using well-draining soil is that nutrients drain faster than the roots of palm trees can absorb.
To counter the effect of nutrient deficiencies, additional soil amendments are often required.
Topsoil is often added to the mix.
A top-dressing of blood meal can increase nitrogen retention.
Adding nitrolized redwood shavings helps retain all nutrients in the soil.
Redwood (untreated) is slow to degrade but being nitrolized, it’s treated with a nitrate fertilizer, increasing its longevity.
Humus is the gold standard in soil amendments and it’s not to be confused with compost.
Compost is the first stage that happens when organic matter decomposes. Once decomposed enough, it’s ready to use as a soil amendment.
Humus is the final stage of decomposition, at which point it can’t decompose any further.
Humus is much richer than compost, but it takes years for compost to reach this stage. When top dressing with humus, only use it sparingly because it will hold moisture for longer.
The main advantage of using humus for palm trees is that the nutrients cling to them for longer. The roots absorb more nutrients than they would from traditional compost.
When adding humus, it’s likely you’ll need to mix it with perlite, vermiculite, sand, or pine bark to help improve drainage.
The end goal with this is for it to retain nutrients but not so much moisture.
The more nutrients your soil retains, the less it will need fertilizing. Nail the soil type and your palm tree will grow well with just a few annual feeds of quality fertilizer.
The best fertilizers for palm trees grown outdoors are slow-release in either granule, spike, or pellet form.
The Best Potting Soil Mix for Palm Trees Indoors
For indoor potted palm trees, the soil needs to be well-draining. General soil mixtures used for houseplants can be used.
Much of the nutrients will be retained in the pot, but that also means you’ll need to repot your palm frequently to avoid excess salt accumulation.
Ideal soil mixes for container-grown palm trees contain a mix of peat moss, shredded bark, and leaf mold.
There are palm potting mixes readily available too if you prefer not to mix your own.
Frequently Asked Questions Related to Soils for Palm Trees
Can clay soils be amended to suit palm trees?
Depending on how much clay material is in the soil, it may be possible. The best types of soil for palm trees are mostly sandy loam. When amendments are needed, it’s much better to have no more than 20% of the soil be amendments, such as perlite, vermiculite, compost, or pine bark. More than 20% of amendments would likely degrade too fast to continue being suitable.
Can palm trees be mounded where the soil isn’t suitable?
Mounding is beneficial when the ground soil isn’t suited. To pull it off, create a raised bed using sandy loam-type soil with a mound large enough to accommodate the root initiation zone (RIZ). The mound should be the same height as the container it’s being taken out of to plant in the garden. Eventually, the roots will embed themselves into the mound of soil and grow the same as they would if planted below ground. Don’t try this with trees though. Remember, palm trees aren’t technically trees because they have no secondary root growth.
Marcel runs the place around here. He has a deep passion for houseplants & gardening and is constantly on the lookout for yet another special plant to add to his arsenal of houseplants, succulents & cacti.
Marcel is also the founder of Iseli International Commerce, a sole proprietorship company that publishes a variety of websites and online magazines.