Hi everyone,

I’m looking to hear about your experiences with foliar feeding on palms, especially regarding species-specific quirks or sensitive new growth.

Here is my current situation: I’m growing 5-year-old Beccariophoenix alfredii in pots (approx. 30 cm / 12" pot diameter for a 60 cm / 24" canopy) on a south-facing balcony (part-shade). The soil is well-drained, and I use soft tap water.

The newest emerging fronds have been coming out very pale / light green, while the older fronds remain a healthy, dark green. Nitrogen deficiency can be ruled out, as well as root-binding.

Since the soil and watering seem fine, I suspect a trace element imbalance — specifically a relative Manganese (Mn) or Iron (Fe) uptake bottleneck during fast summer growth.

I’m using a high-quality specialty palm fertilizer (RPS), but to bypass any potential root/substrate absorption barrier, I’ve decided to start a foliar feeding regimen:

• Sprayed at dusk / late evening to prevent leaf burn.

• Applied at a diluted rate (approx. 1/4 of the recommended soil dosage).

• Focused on the undersides of the fronds and the emerging spear.

My questions:

1. Has anyone here successfully treated pale new growth on Beccariophoenix alfredii (or similar species like Dypsis / Archontophoenix) using foliar sprays?

2. Did you use a standard chelating micro-nutrient blend (EDTA/amino acids), or did you need a pure Manganese spray?

3. Is foliar feeding also a good idea for my tropical understory palms? Kerriodoxa, Joey, Calyptrocalyx...

Thanks in advance for sharing your insights and experiences!

Best regards,

Matti

PS: The last post I found about this topic is 16 years old...

Be careful if you’re making up your own trace element mix. If using a specific brand trace element use it at or under the manufacturer’s recommendations, a little goes a long way. A lot of palms from different places around the globe have very different soils. So just foliar feeding everything may not work out well. Chose wisely, myself I would just foliar feed with a seaweed extract or something else that is organic. Spraying a heap of trace elements around can be a bit dangerous for some palms, it would be best to spray on cool day or a rainy day to avoid such leaf burn issues.

The biggest issue is incorrect diagnosis and locking up your soil causing more damage than good. Choose carefully for each specific varietie.

I don’t use trace elements I prefer a good healthy soil mix that helps prevent such deficiencies, I do get deficiencies in my palms but iam not too worried about such an issue, next time I repot it’s a new healthy soil mix that will help with any deficiency at hand.

A regular organic fertiliser is my favourite for fertiliser applied through foliar feeding techniques, a Venturi on the end of a hose with a container full of high strength organic fertiliser, the Venturi does the dilution for me. Every spring and summer watering is fine this way. No fertiliser in autumn or winter!

This winter I only watered my whole nursery twice and let Mother Nature do the rest, winter is a tricky time to water and a no no for fertiliser.

Every grower is different in there approach to fertilising, I prefer not to blast away with a heap of stuff and just go organic.

Iron deficiency is characterized by yellowing of new growth. Overwatering causes a low oxygen soil and iron deficiency. My expectation with foliar feeding is that the non waxy leaves are the ones that will absorb it, not waxy leaves like alfredii. I might try to limit the sunlight if it gets more than 4 hrs direct sun and increase watering interval a little and see if it greens up in a few months. Overwatering in pots leads to more limpness in the leaves. Foliar sprays have limited absorption into the leaf but they have worked OK for me on non palms. The highest penetrating fertilizer into the leaf is N2 dissolved in rain as its a small, nonpolar molecule that readily passes protective lipid membranes. Obviously I dont know all the history of your palm or even the soil it is in. If there is a drain hole in the bottom of the pot it should get somewhat dry before the next watering. Not sure I could do any better in Germany, its way out of habitat conditions there. Remember that adding different micronutrients separately can lead to a deficiency if they are at ratios that change the competition for uptake. For example calcium, and Mg are chemically similar in the same family so they can compete and typically palms prefer 3:1 calcium:magnesium. If it were 1:1 calcium:magnesium, calcium uptake would be negatively impacted and if it were 10:1 Ca:Mg, Mg uptake would be limited. This is why I don't add individual micros, just formulations of them for palms.

Google AI sums factors in Fe deficiency up:

Iron (Fe) deficiency in palms is rarely caused by an actual lack of iron in the soil. Instead, it stems from cultural or environmental factors that inhibit root respiration and restrict active nutrient uptake by the root system. [1, 2]

Primary Causes

• Poor Soil Aeration: Compacted or heavy soils reduce oxygen availability, stunting root metabolism and nutrient absorption. [1, 2, 3]

• Deep Planting: Palms planted too deeply place the root ball below the oxygen-rich soil layer, preventing proper root respiration. [1, 2]

• Root Rot Diseases: Fungal pathogens destroy active root surface area, drastically lowering the plant's ability to intercept and absorb iron. [1, 2]

• Overwatering / Waterlogging: Excess water displaces soil oxygen and suffocates root systems. [1, 2, 3]

• Substrate Degradation: In potted or container-grown palms, decomposing or breaking down growing media strangles the root zone. [1, 2]

• Nutrient Imbalances: Excessive uptake of heavy metals or competing ions—such as manganese, zinc, copper, ammonium, or phosphate—can induce iron deficiency symptoms. [1, 2]