This article was last updated by on

Begonia Soil and Fertilizer – With ‘Buy & Apply’ Recommendations

Begonia is a perennial plant with spectacular leaves and flowers that get pronounced with proper soil and fertilizer use.

Generally, Begonia loves well-draining, acidic soil with medium moisture retention. Also, Begonias prefer organic matter or compost with perlite and peat moss. Also, it requires balanced fertilizers every 2 weeks during its growing season.

The roots and stems of Begonia are vulnerable to cold, and you must ensure they are intact over wet soils.

So, read thoroughly to find out the ideal Begonia soil and fertilizer.

What Kind of Soil Does Begonia Need?

Begonia is a genus native to subtropical and tropical climates with around 2547 species.

They grow best in soil that mimics their native home.

Begonia loves moisture and demands damp soil with well-drainage. Hence, the best Begonia soil mix ratio includes equal amounts of organic perlite and peat moss.

Image represents a potted Begonia plant
Begonia plants need a porous potting mix to increase the drainage capacity of the soil and planter.

Generally, you can mimic its natural home indoors by managing light, humidity, temperature, soil requirements, and fertilizer application.

Here’s what you need to consider before preparing proper Begonia soil.

Soil FactorsSpecifications
TypeWell-draining potting soil
MaterialsA potting mix with organic and inorganic materials such as peat moss, perlite, coco coir, compost, etc.
pH LevelSlightly Acidic (5.2-6.0)
CompactionLow (well-percolated)
Drainage1-2 inches per hour
TextureSandy loam
Water Retention20-45%

Prevent temperature drops below 55°F during the night

Nothing less than 40°F in fall & winter
NutrientsBalanced proportion of nitrogen, phosphorus, and potassium with micronutrients (magnesium, calcium, iron, sodium, zinc, etc.)
FertilizerEvery 2 weeks during its active growth and monthly in winter with diluted liquid fertilizer
ToxicityPesticide and fertilizer salts with aluminum, lead, and chromated copper arsenate will lead to soil toxicity
ChangeEvery 3 years during the spring

1. Drainage Capacity

Begonia is a thirsty plant loving a well-draining soil mix that stays moist but not too wet.

Without proper drainage, the delicate roots will rot, and the plant will suffocate.

Begonia prefers faster-draining soil (1-1.5 inches per hour) to retain water without getting soggy or too wet.

For superior water retention and drainage, you can add peat moss and perlite to the potting mix.

Also, use clay, ceramic, or terracotta pots with bottom drainage holes to prevent waterlogging.

Moreover, you can add a layer of gravel or pebbles at the bottom of the pot to promote better drainage.

What do you feed Begonias in pots?

You can feed pot-grown plants weekly with tomato feed or use a slow-release fertilizer pellet during transplanting or repotting.

However, stop feeding the plant in early fall. You can also halt watering from mid-fall until spring and deadheading to remove spent blooms.

Look at the following short video to water your Begonia plant and increase the drainage capacity of the soil.

2. Soil Aeration

Like other indoor plants, the Begonia requires fluffy soil for easy access to oxygen.

Potting soil of indoor Begonias becomes compact over time and devoid of oxygen if not changed periodically.

Lack of oxygen will cause the Begonia to wilt and suffocate and the roots to rot over time.

Occasionally changing soils during repotting, transplanting, or propagation to rejuvenate oxygen levels will significantly help your plant.

You can easily aerate the soil by slowly puncturing small holes in the topsoil with a stick without hurting the roots.

3. Soil Texture & Structure

Soil texture and structure decide major soil characteristics. Generally, garden-grown Begonias can thrive in sandy loam soil.

However, indoor Begonias prefer sandy loam granular soil with peat moss, organic vermiculite, and perlite. 

Due to its thirsty nature, try watering Begonia often. It may lead to water clogging if soil drainage is not proper.

Typical garden clay can quickly become compact discouraging oxygen circulation. It leads to drooping and yellowing leaves.

Therefore, use light granular soil or soilless potting mix for the Begonia plant as they emphasize well-drainage.

Pro Tip!

Add eggshells and leftover chicken bones to fortify the Begonia soil with calcium to optimize soil quality.

4. Soil Temperature

Soil temperature is significant in plant growth as it influences soil moisture, aeration, and nutrient availability.

According to research, soil temperature influences root growth, resulting in overall plant growth.

Keeping indoor Begonias within 55-72°F will be optimal. You can also use a heating pad to raise the temperature of the soil.

However, prevent the temperature from falling below 55°F as they cannot tolerate cold temperatures.

Do not place the Begonia near a drafty window or cooling vent because it may wilt from temperature stress.

Moreover, you can use a digital thermometer to ensure uniform temperature for most.

Image represents repotting Begonia plant
In root rot, you must change the soil and offer a new pot for your Begonias.

5. Slight Acidic Soil

Begonia prefers its soil to be slightly acidic because acidic soil breaks down nutrients in the soil, making them available to the plant.

While excessively acidic soil will prevent nutrient supply to the roots, alkaline soil releases sodium into the soil.

Therefore, it is best to maintain the soil pH for Begonia between 5.2 and 6.

Always check soil pH with a pH meter to ensure it is within the recommended range.

Additionally, soil bacteria, toxic substances, and soil structure are other factors that can affect soil pH.

Adding organic substances like compost, pine mulch, leaf mold, and sulfur powder will increase soil acidity.

If you want to know more about the soil needs of plants, watch the following video.

6. Organic Matters & Nutrients 

Begonias will adore you if you add compost or organic fertilizer to the soil.

Additionally, organic matters such as compost, wood chips, bark, and mulching would make the soil more fertile.

However, be careful with mulching as Begonia roots start to rot due to wet conditions.

There are 2 different soil nutrients that promote plant health. They are listed below.

Macronutrients Nitrogen (N), Phosphorus (P), Potassium (K), Sulfur (S), Magnesium (Mg), and Calcium (Ca)
MicronutrientsBoron (B), Zinc (Zn), Manganese (Mn), Iron (Fe), Copper (Cu), Molybdenum (Mo), Chlorine (Cl)

These nutrients are present in the soil where Begonias naturally grow.

Therefore, use certified organic fertilizer only to maintain the nutrients available in the soil for Begonia.

Soil/Potting Mix for Begonia

Other readymade potting mixes are available for Begonia to start easily.

However, you can prepare a custom potting mix yourself at home. So, here is a detailed process to make the best mix.

Recipe 1

  • Two parts Perlite
  • One part of Coco Coir
  • Half part compost
  • Half part sand

Recipe 2

  • One part Perlite
  • One part Vermiculite
  • One part Peat Moss
  • Half part Orchid Bark
  • Half part compost
  • Half part sand

Pro Tip!

You can also use a 4:1:1 ratio mix of leaf-mold decay, garden loam & coarse sand to prepare regular soil for Begonia.

Common Signs of Using the Wrong Potting Mix

Here is a list of common signs if you are using the wrong potting mix for Begonias.

  • A fishy or unpleasant moldy odor from the soil
  • White molds on the soil surface
  • Pest infestations (mites, mealy bugs, and scales)
  • Bacterial leaf spots and the occurrence of Rhizoctonia crown rot
Image represents brown leaf margins in Begonia leaves
Brown leaves are a result of overfertilization.
  • Dense soil with water retention
  • Rotting stem or root base (Pythium root rot)
  • Brown leaves and leaves falling off
  • Crispy brown leaf tips and margins

What Kind of Fertilizer Is Best For Begonias?

Begonias need frequent fertilizer application during their growing season to thrive. 

Generally, Begonia requires an NPK ratio of 20-20-20 every 2 weeks in spring and summer.

Besides, Begonias don’t go dormant during winter, so they need scant fertilizer application.

Do You Know?

Slow-release fertilizer for Begonia is less likely to cause fertilizer burn in the plants as it avoids salt buildups in the soil.

Signs Begonia Needs Fertilizing

Begonia will display signs when they lack nutrients.

  • Droopy or yellow leaves
  • Stunted leaf growth
  • Dull leaves and weak flower buds
  • Leaf curling with yellowish-brown leaves
  • Interveinal chlorosis

Overfeeding your Begonia will cause crispy brown spots, yellowing leaves, and wilting leaves with root rots.

Therefore, reduce fertilizing application during its dormant period to avoid overfertilization.

What is the best way to fertilize Begonias?

  • Scoop out slow-release fertilizer in small amounts and sprinkle it around the plants.
  • To cover most of the soil, sprinkle the fertilizer, but avoid falling it into plant parts.
  • Water the soil before fertilizer application so nutrients can seep into deeper soil layers.
  • Even though slow-release does not need water, you can use some when applying the fertilizer.
  • However, dilute liquid fertilizer to the required strength as instructed per pack before using.

Pro Tip!

Weeds often pose a nuisance for Begonias as they compete for soil nutrients.

Hence, you can use Miracle-Gro Shake ‘N Feed and Miracle-Gro Garden Weed Preventer in the soil to control weeds from growing.

Begonia Soil & Fertilizer Mixture for Sale

The best Begonia soil and fertilizer blend must retain a well-draining and nutrient-rich pure mixture of substances.

Look at some of the commercial recommendations below.

Potting SoilFertilizer
Miracle-Gro Indoor PottingOsmocote Plus (NPK: 15-9-12)
Miracle-Gro Moisture Control Potting MixJobe's Fertilizer(NPK:8 -9-12)
All Purpose Indoor Houseplant Potting Soil MixBonide Plant Food (NPK:10-10-10)
Espoma Organic Potting SoilBurpee Organic Bloom

From Editorial Team

Leftover coffee grounds for Begonias!

Begonias relish the frequent application of NPK during the growing seasons.

So admixing coffee grounds to the soil will help the plant to develop flower buds and vibrant inflorescences.

Leave a Reply

Your email address will not be published. Required fields are marked *