Soursop Nutrient Deficiency: Signs, Causes and the Fertilizer That Fixes It

Soursop nutrient deficiency signs, old leaves and young leaves

Shows first on the old leaves

Shows first on the young leaves

Before you buy fertilizer for a soursop nutrient deficiency

So use the table to pick the likeliest soursop nutrient deficiency, then read its section below. Also keep in mind that dry soil, standing water, cold nights, a pest or a disease can look the same. That is why it pays to check the roots and the whole field first.

Nitrogen deficiency in soursop

Older leaves near the base slowly lose their green and turn an even pale green over the blade, stalk and veins. As it gets worse all leaves turn yellow and lose their shine, the old leaves drop early. The plant stays short with a thin stem. Nitrogen shortage hurts guyabano growth more than any other nutrient, and can cut the plant's dry weight by 94 percent. You see it most at this stage: seedlings and young trees in fast growth, and bearing trees during fruit growth.

Why nitrogen deficiency happens in guyabano

Sandy or eroded soils low in organic matter, trees that get no manure or fertilizer, and heavy rain that washes nitrogen down.

How to tell it apart

Long droughts also make guyabano shed leaves, so check soil moisture before you blame nitrogen. Sulfur shortage also gives pale, small leaves, but it shows on the young leaves while the lower leaves look normal. To be sure, A leaf test shows low nitrogen. Take the sample leaves from midway along branches in the middle third of the canopy. New leaves that come out green after a nitrogen dose confirm it.

What to apply for nitrogen deficiency

Give nitrogen in small doses a few times a year, spread under the canopy and watered in. Give 10 10 10 four times a year: about 0.23 kg per tree in all the first year, 0.45 kg the second. 1.4 kg a year after that. In the Philippines, Complete 14 14 14 is the usual complete fertilizer. Add Urea 46 0 0 or Ammonium sulfate 21 0 0 when leaves are pale. Mix in manure or compost. Give it when the rains begin and again before they end.

• Complete 14 14 14
• Urea 46 0 0
• Ammonium sulfate 21 0 0

Sold here with nitrogen: Atlas Granular Urea (46 0 0) by Atlas Fertilizer, Amigo Planters Ammonium Chloride by La Filipina (25 0 0), Agripower 46 0 0 (Locally Blended) Coated by Green Acres Agri Tech and Calcipro by Ramgo (15.5 0 0 with 18.8 percent calcium). Check the FPA registration on the bag and follow the label rate. For the how and when, see our guide to urea fertilizer, and the page on nitrogen deficiency in every crop. In anee.io, Anee, the smart farm technician, reads a photo of the leaf and tells you which nutrient is short.

To keep it away, feed in several small doses through the year rather than one big dose, keep a thick mulch over the shallow roots, and add manure every year. Let a soil test and the crop's color set the season's nitrogen.

Potassium deficiency in soursop

At first the foliage turns a deep green and the young leaves come out a little smaller. Then older leaves yellow along the margin, starting at the tip. The yellow moves inward between the veins, from yellow green to brown as the tissue dies. Sometimes the edges turn orange yellow before they brown. In severe cases the lower leaves fall and growth stops. You see it most at this stage: bearing trees during fruit growth, and young trees on sandy soil.

Why potassium deficiency happens in guyabano

Sandy, leached soils and heavy rain, and years of fruiting with no potash returned. Guyabano seedlings use more potash and nitrogen than any other nutrient.

How to tell it apart

Magnesium shortage also starts on older leaves, but it yellows along the midrib while the leaf margins stay green. Salt or fertilizer burn scorches margins quickly after a heavy dose. To be sure, A soil test for potash and a leaf test of leaves from the middle of branches in the middle third of the canopy.

What to apply for potassium deficiency

Apply Muriate of potash 0 0 60 or Sulfate of potash 0 0 50 under the canopy in split doses, following the soil test. A fertilizer with 3 percent nitrogen and 10 percent each of phosphate and potash suits guyabano well. In the Philippines a Complete 14 14 14 plus Muriate of potash does the same job. Give 200 to 500 grams of Muriate of potash 0 0 60 a bearing tree a year in two doses, more while fruits are filling.

• Muriate of potash 0 0 60
• Sulfate of potash 0 0 50
• Complete 14 14 14

Sold here with potassium: Atlas Muriate of Potash (MOP) by Atlas Fertilizer (0 0 60), Simplot Sulfate 0 0 50 by Nutranta, Potassium Nitrate by Parafield (13 0 46) and Qrop Mix Production 14 0 23 plus 13 Cao by Farmtech Agriland (14 0 23 with 9.3 percent calcium). Check the FPA registration on the bag and follow the label rate. For the how and when, see our guide to potash fertilizer, and the page on potassium deficiency in every crop.

To keep it away, give potash in every feeding of bearing trees, and return fallen leaves and prunings as mulch.

Phosphorus deficiency in soursop

The upper leaves often show it first, coming out smaller and narrower with curled edges and tips that point down. The lower leaves turned light green and were held close against the stem. Growth slowed sharply. The signs can also start on the lower leaves and move up. Leaving out phosphorus was the third most damaging omission for guyabano, after nitrogen and calcium. You see it most at this stage: seedlings and young trees, and trees on poor acid soils.

Why phosphorus deficiency happens in guyabano

Acid and eroded soils low in organic matter, and no phosphate at planting. Guyabano orchards are often low in phosphorus. In a quarter of them it was the most limiting nutrient.

How to tell it apart

Nitrogen shortage gives an even pale yellow without the narrow, curled leaves. Mealybugs and scale insects feed on guyabano and weaken new growth too. To be sure, A soil test for available phosphorus and pH. A leaf test of leaves from the middle of branches in the middle third of the canopy.

What to apply for phosphorus deficiency

Work Superphosphate 0 20 0, 16 20 0 or Ammonium phosphate 18 46 0 into the soil under the canopy, following the soil test, together with manure or compost. A 10 10 10 or a 3 10 10 mix also supplies a fair amount of phosphate. Complete 14 14 14 can be used in the Philippines. Give 200 to 500 grams of Complete 14 14 14 a young tree, up to 1 to 2 kg a bearing tree, when the rains begin.

• Superphosphate 0 20 0
• 16 20 0
• Ammonium phosphate 18 46 0
• Complete 14 14 14

Sold here with phosphorus: Philphos 18 46 0 (Di Ammonium Phosphate), Atlas Super Gro (16 20 0) by Atlas Fertilizer, Amigo Planters Granular Single Super Phosphate by La Filipina (0 18 0 with 11 percent sulfur) and Triple Super Phosphate by Newman Chemicals (0 46 0). Check the FPA registration on the bag and follow the label rate. For the how and when, see our guide to 16 20 0 fertilizer, and the page on phosphorus deficiency in every crop.

To keep it away, put phosphate and manure in the planting hole and give phosphate in the yearly feeding. Lime very acid soils according to the soil test. Guyabano grows best between pH 5 and 6.5.

Calcium deficiency in soursop

The youngest leaves show it first: the leaf tip and the upper edge die and turn a burnt dark brown. But the rest of the leaf stays normal green. The burnt part rolls over on itself with the edges turned up. Later leaves drop early and the shoot tip stops growing. Yellowing may also show around the edges and between the main veins before the tissue dies. Leaving out calcium was the second most damaging omission after nitrogen. You see it most at this stage: young trees and new flushes, most often on acid soils.

Why calcium deficiency happens in guyabano

Strongly acid, leached soils low in calcium, which are common under heavy rainfall. Dry spells that slow calcium flow to the growing tips. Leaf calcium is often low in guyabano orchards.

How to tell it apart

Potassium shortage burns the edges of older leaves first, not the newest leaves. Boron shortage also damages growing tips, but young leaves come out small and misshapen and fruit set fails. To be sure, A soil test for pH, calcium and magnesium. A leaf test of leaves from the middle of branches in the middle third of the canopy.

What to apply for calcium deficiency

On acid soils, spread Agricultural lime or Dolomite under the canopy to lift the pH. Guyabano likes 5 to 6.5. Take the amount from the soil test. Where the pH is already fine, Gypsum supplies calcium without changing the pH. Give Gypsum at 50 kg per hectare for custard apple, a close cousin. A Calcium nitrate spray on young flushes helps while the soil dose works. Follow the label. For quick help on fruit and young leaves, spray Calcium nitrate at 0.5 to 1 percent (80 to 160 grams in a 16 liter sprayer) every 7 to 10 days from fruit set.

• Agricultural lime
• Dolomite
• Gypsum
• Calcium nitrate

Sold here with calcium: Planters Products Lifelime (36.2 percent calcium), Dolomite by A6 Agrisource (24 percent calcium and 11 percent magnesium), Calcipro by Ramgo (15.5 0 0 with 18.8 percent calcium) and Philphos Gypsum (22.2 percent calcium and 17.4 percent sulfur). Check the FPA registration on the bag and follow the label rate. For the how and when, see our guide to fertilizer for tomatoes, and the page on calcium deficiency in every crop.

To keep it away, test the soil every few years and lime before the pH drops too low. Keep the soil moist with mulch during dry spells. Keep potash in balance with magnesium and calcium.

Boron deficiency in soursop

The signs on guyabano are like those on other fruit trees. Young tissues suffer first: shoot tips stop growing and may die, and new leaves come out small and misshapen. Pollination and seed development fail, so fruit set is poor and fruits can grow lopsided or crack. Leaf boron is often low in guyabano orchards. You see it most at this stage: flowering, fruit set and early fruit growth.

Why boron deficiency happens in guyabano

Sandy, leached and acid soils low in organic matter, and long dry spells. On acid tropical soils below pH 6.5, boron and zinc are the trace nutrients to watch most in guyabano.

How to tell it apart

Poor pollination is the main cause of low yield in guyabano, and it also gives lopsided fruits. So do not blame boron for every misshapen fruit. To be sure, A leaf test for boron of leaves from the middle of branches in the middle third of the canopy, and a soil test. Spray a few branches with boron before flowering and compare fruit set. In a soil test, less than 0.5 ppm of boron is low.

What to apply for boron deficiency

Apply Borax to the soil under the canopy or spray Solubor on the leaves before flowering, following the soil test and the label. Do not overdose, because too much boron burns leaf tips and edges. Give 25 to 50 grams of Borax a young tree and 50 to 100 grams a bearing tree a year, spread evenly under the canopy. A spray of Borax or Solubor at 0.1 to 0.2 percent (16 to 32 grams in a 16 liter sprayer) before flowering also works. Use the soil dose or the spray, not both.

• Borax
• Solubor

Sold here with boron: Etifert 11 (Borax Decahydrate) by Zetryl Chem (11 percent boron), Fertibagra 15G by Unilox Far East Resources (14.6 percent boron), B17 (Boric Acid) by Newman Chemicals (17 percent boron) and Better Yield by Bacphil Planters Fertilizer (0 0 0.9 with 10 percent boron). Check the FPA registration on the bag and follow the label rate. For the how and when, see our guide to foliar fertilizer, and the page on boron deficiency in every crop.

To keep it away, add compost every year, and on sandy or acid soils include boron in the micronutrient sprays before flowering.

Magnesium deficiency in soursop

Older leaves in the middle of the plant show it first, with light yellowing along the midrib. The midrib and the side margins of the leaf stay green. As it gets worse the yellow band turns orange, the leaves drop early, and the plant grows less. The yellowing sits between the veins, starting beside the midrib and spreading out toward the edges. You see it most at this stage: bearing trees and trees fed heavy potash, during fruit growth.

Why magnesium deficiency happens in guyabano

Acid, sandy and leached soils, and heavy potash fertilizer, which competes with magnesium.

How to tell it apart

Potassium shortage also starts on older leaves, but the yellow and brown start at the tip and margin and move inward. Nitrogen shortage yellows the whole leaf evenly, veins included. To be sure, A soil test for magnesium, potash and calcium together. A leaf test of leaves from the middle of branches in the middle third of the canopy.

What to apply for magnesium deficiency

On acid soils apply Dolomite, which supplies both lime and magnesium. Take the amount from the soil test. Where the pH is already fine, spread Magnesium sulfate (Epsom salt) or Kieserite under the canopy and follow the label. Give 100 to 250 grams of Kieserite or Magnesium sulfate a tree a year, or Dolomite on acid soil. Put the soil dose in before planting or when the rains begin. Sprays show results in 10 to 14 days.

• Dolomite
• Magnesium sulfate (Epsom salt)
• Kieserite

Sold here with magnesium: Dolomite by A6 Agrisource (24 percent calcium and 11 percent magnesium), Agsmart Kieserite Granule (20 percent sulfur and 16.3 percent magnesium), DDDD Planter's Choice Magnesium Sulphate Monohydrate by Modern Time (15.1 percent magnesium) and Zetryl MAG 9 by Zetryl Chem (9 percent magnesium). Check the FPA registration on the bag and follow the label rate. For the how and when, see our guide to complete fertilizer, and the page on magnesium deficiency in every crop.

To keep it away, balance potash with magnesium according to the soil test, and use Dolomite rather than plain lime on acid soils.

Soursop nutrient deficiency questions