pH for indoor plants is one of the little-known facts about houseplants. Although houseplants can grow outside of their ideal pH range, the further the pH deviates from the ideal range, the less healthy the plant will be, meaning it won’t grow as fast or upsize as well. So, it’s important to understand pH, why it’s important, and how to check and improve it.
What is the pH of soil?
pH is an abbreviation for the terms: “pondus hydrogenii” (hydrogen activity). In agriculture, pH is an indicator of the acidity or alkalinity of the soil, which has a great impact on plant growth. It is assessed by the concentration of hydrogen ion (H+) and hydroxide (OH-) in the soil.
If the H+ ion content is high and active, the soil is acidic. On the contrary, if the H+ ion content is low, it is alkaline. In case the amount of hydrogen (H+) is balanced with the amount of hydroxide (OH-), the soil is neutral, the pH is approximately 7.
The pH scale ranges from 0 – 14, for plants we can focus on levels between 4.0 – 8.5. A value of 7.0 is considered neutral pH, below 7.0 is acidic, above 7.0 is alkaline.
Why is pH important in growing plants indoors?
As you know, all plants need nutrients to grow healthily. They need macronutrients such as nitrogen, phosphorus and potassium, as well as micronutrients and minerals including calcium, magnesium, iron, copper, etc. If plants cannot access these nutrients, deficiencies and other serious health problems can result.
The problem with houseplants is that they can only absorb nutrients within a small pH range, which fluctuates around 6–7 when growing in soil. If the pH is lower or higher than that, the plant cannot absorb nutrients, even if they are present—thus causing nutrient deficiencies through the phenomenon of “nutrient locking.”
In places where houseplants thrive in the wild, the soil is often slightly acidic; therefore, houseplants will also prefer a slightly acidic environment. However, how you grow your houseplants also plays a role in creating the optimal pH level for your plants. Houseplants grown hydroponically or without soil need an even lower pH than those grown in soil.
Best pH for Houseplants
The ideal pH for most indoor plants is between 5.5 and 6.5.
The ideal pH level for each plant is different, and depends on the time and stage of growth. Keeping the pH between 6 and 7 will help your plants thrive. In general, the best pH level for indoor plants is 6.5, the level at which all nutrients can be absorbed.
The effects and effects of pH
| pH | Affect |
| Below 4.0 | Root Damage / Root Damage |
| 4.0 – 4.9 | Nutrient Leaching / Nutrient Restriction |
| 5.0 – 5.9 | Good pH Level / Good pH |
| 6.0 – 6.5 | Ideal pH Level / Ideal pH |
| 6.6 – 7.0 | Acceptable pH Balance / Acceptable pH |
| 7.1 – 8.5 | Poor Nutrient Uptake / Poor Nutrient Absorption |
| Over 8.5 | Root damage |
Ideal Soil pH for Houseplants
| Houseplants | Ideal pH |
| Aloe Vera | 6.0 – 7.0 |
| Aglaonema | 5.5 – 6.5 |
| Alocasia | 5.0 – 6.0 |
| Anthurium | 5.5 – 6.5 |
| Aspidistra (Cast Iron) | 5.5 – 7.0 |
| Bamboo | 5.0 – 7.5 |
| Begonia | 6.0 – 8.0 |
| Cactus | 4.5 – 6.0 |
| Colocasia | 5.5 – 7.0 |
| Coleus (Nettle) | 6.0 – 7.0 |
| Cordyline | 6.5 – 8.0 |
| Calathea | 4.5 – 5.5 |
| Dracaena (Prosperity) | 6.0 – 6.5 |
| Dieffenbachia (Dieffenbachia) | 5.5 – 6.5 |
| Epipremnum | 5.0 – 6.0 |
| Platycerium | 5.5 – 6.5 |
| Palm | 6.0 – 8.0 |
| Monstera | 5.0 – 6.0 |
| Homalomena | 6.0 – 7.0 |
| Fittonia (Velvet) | 6.0 – 6.5 |
| Fern | 4.5 – 6.0 |
| Orchid | 5.5 – 6.5 |
| Peperomia | 6.0 – 7.5 |
| Philodendron | 4.5 – 6.0 |
| Pothos (Betel) | 6.1 – 6.5 |
| Oxalis | 6.0 – 8.0 |
| Rubber fig (Red bud) | 5.5 – 7.0 |
| Spider plant (Orchid) | 6.1 – 6.5 |
| Sansevieria | 5.5 – 7.5 |
| Succulents | 5.5 – 6.5 |
| Snake Plant | 5.5 – 7.5 |
| Syngonium | 5.5 – 6.5 |
| Tradescantia (Thai jasmine) | 6.0 – 7.0 |
| Zamioculcas Zamiifolia (ZZ plant) (Golden money) | 6.0 – 7.0 |
See also Plant pH Preference List:
Tổng hợp kiến thức trồng cây trong nhà
- ☀️ Ánh sáng cho cây trong nhà: phân loại, hướng dẫn chi tiết
- 🧪 Độ pH cho cây trong nhà: giải thích, hướng dẫn chi tiết
- 🐌 Giá thể dành cho các loại cây trong nhà
- 💦 Tưới nước cho cây trong nhà
- 🌡️ Nhiệt độ cho cây trong nhà: giải thích hướng dẫn chi tiết
