A citrus is a fruit group composed of various fruits such as sweet orange, lemon, limes, grapefruit, and others. All of the citrus fruits mentioned here are commercially grown. On the other hand, most people who engaged in indoor gardening began to grow various fruits. 

When the new technique HDP (High-Density Plantation) was presented, the idea of growing fruits inside emerged. As a result, you will find all of the necessary information about growing citrus indoors right here.

In this article, we’ll go over the specifics of how to grow citrus fruit indoors, such as what HDP is and which fruits you can grow, cultural operations, and plant protection. Finally, we’ll go over some frequently asked questions. So stay tuned!

What is HDP?

So, before we proceed, let us try to explain to HDP. As previously stated, HDP stands for High-Density Plantation, which is a method of growing a greater number of plants per unit area. Fortunately, this technique is used in fruits. 

This technique allows you to reduce row-to-row and plant-to-plant distances while controlling height up to an optimum limit. Many examples include mangoes, citrus (Kinnow, limes, lemons), and guava, which are grown using the HDP technique by progressive farmers all over the world. These fruits can be grown indoors as well.

Growing citrus indoors from seed 

Many things changed from traditional to advanced as time passed. Similarly, most fruits in horticulture are advised by experts to be grown asexually to achieve faster results. Rootstock is commonly used to grow from seed, and I hope you are familiar with these (scion & rootstock) phenomena.

Method

Except for lemons, the rootstock is used with many scion varieties. If you want to prepare the stocks, you can use Rough Lemon or Sour Orange. Fruit is crushed for this purpose, and seeds are sown in seedling trays or grown directly in the soil. 

After 6-12 months depending upon the climate, the rootstock reaches maturity and pencil thickness. At which point it is transplanted to natural soil and allocated with scion via grafting or budding technique in the following growing season.

What kind of plants/trees can we grow indoors?

Many citrus fruit species have cultivars that can be grown indoors, such as Sweet Orange (Musambi, Fuetrell’s Early), Mandarin (Kinnow), Grapefruit (with pigmented and non-pigmented varieties), Sweet Lime, Kagzi Lime, Lemons, and so on. These are some indoor citrus fruit-growing options for you. Let’s go over some key facts for growth.

1. Oranges

Oranges are divided into four different sub-categories, which I will not go into. But I will describe some of its cultivars such as Mosambi and Feutrell’s Early. Both cultivars grow to a short to medium (6-12ft) height and have a shallow root system. As a result, you can imagine how you can manage your indoor environment.

A large container with dimensions of 4×2 ft is ideal for growing citrus. Because of their higher juiciness content, these cultivars are ideal for juice production. One thing I’d like to mention here is that a prepared nursery plant will bear its first fruit after one and a half years. Otherwise, manually budding these cultivars on your prepared stock would take more than three years. This would be a good to fit for the best indoor orange trees.

2. Mandarin

This is the most popular species, and the best-flavored cultivar is called Kinnow. Kinnow stands at a medium height and is easier to handle. A container or large pot is useful for anchoring, and its depth should not be too shallow. In general, take a 1.5-year-old plant from the nursery and place it and care for it.

Maintain its height and spread to make it lighter in weight. Another technique is ‘pruning,’ which is used to remove unnecessary branches, shoots, and suckers from plants in order to reduce their burden. Kinnow begins fruiting after three years, and nursery-prepared plants take half that time. In this way, Kinnow is considered the best mandarin indoor tree as well.

This specie has many cultivars that work in different zones. Kinnow has a native climate in California that is similar to almost subtropical nature all over the world.

3. Grapefruit

Grapefruit cultivars are classified into two main categories. The first is pigmented, while the second is non-pigmented. Many progressive farmers grow non-pigmented varieties in general. It is primarily grown in large quantities for pharmaceutical purposes.

There are numerous varieties available, including Foster, Shamber, Marsh, Pink Ruby, and many more. Non-pigmented varieties are easily used for juice production. Non-pigmented varieties also have a longer shelf life than pigmented varieties. That is why it is most common among citrus farmers. 

4. Limes and Lemons

These are two groups of smaller citrus fruits that are distinguished by certain characteristics. For example, limes are green in color and relatively smaller when harvested, whereas lemons are larger and yellow in color.

We’re not going to get into the specifics of their definitions. Fortunately, you have a wide range of options from which to choose. Indoors, sweet limes, lemons, and Kagzi lemons are commonly grown. Their odor and smell from plants and fruit are distinct. These plants, which we prioritized, are the most popular in the summer.

These are the species we recommend for indoor cultivation. Now we’ll make a summary of how many people are interested in growing citrus. Mandarin cultivar Kinnow first, followed by Mosambi, Feutrell’s Early, limes and lemons, and grapefruit. This is the broad priority we presented to you.

Recommended intercultural operations

Agronomic practices such as weeding, hoeing, watering, fertilization, and chemical sprays are examples of intercultural operations. We all know that agronomic operations in large field orchards require a lot of labour. However, at home, where you are only responsible for plant management. You should be aware of the following points.

1. Climate

Citrus grows best in subtropical climates with temperatures ranging from 15 to 30 degrees Celsius. In the case of an indoor plant, keep it at a lower height with optimal spreading to meet the sunlight requirement.

Plants should not be placed near a wall or anywhere that receives less than six hours of light per day. Importantly, plants in their early stages require protection from hot summer sunlight. Cover the young plants during the day to accomplish this.

2. Soil

A sandy loam with good drainage and water-holding capacity is the best soil for indoor citrus trees. Remember to prepare the soil whenever you want to transplant a plant into a pot. For increased productivity, use a combination of organic and soil. You can do this by using the nursery’s synthetic mix, or by preparing a 1:1:1 mixture of sand, silt, and FYM (Farm Yard Manure).  

3. Irrigation

Citrus has a shallow root system and is also known as a surface feeder. That is why they require a sufficient amount of water. In the summer, younger plants require watering once or twice a week until they established a root system. 

Importantly, many factors such as soil, climate, temperature, age, and so on are taken into account for water irrigation. Citrus is sensitive to water stress.

4. Fertilization

A short plant with a small root area requires fair amount of fertilization. If you have prepared a good media composed of organic matter, nutrients, and synthetic fertilizer at the time of plantation. Then there is no need to look after it. 

Apart from the media, synthetic fertilizers such as Urea should be applied after six months so that the plant can complete its vegetative growth. Again, not directly advised, but after consulting with plant experts.

5. Plant protection

Citrus plants require less attention in terms of pest and disease protection when grown indoors. However, there are a few things you must understand, which are as follows:

• Check the health and vigor of a plant before purchasing it from a nursery.
• If you want to prepare the rootstock, fumigate the soil and disinfect the seeds.
• Take a 1-1/2-year-old healthy budded plant with a pencil thickness.
• With the time, remove the suckers.
• Pruning is necessary to keep the shape and vigor of the plant.
• Remove the weeds from beneath its canopy.

FAQs

Citrus fruit growing indoors is not a new concept, but if you’re a beginner looking to take some quick notes. Then these frequently asked questions will get you started.

How do develop an orange tree indoors from the seed?

Oranges are classified into four types (sweet, less sweet, acidic, and non-acidic) within the citrus genus. The sweet orange species is the most common, with numerous cultivars such as Valencia, Navel, Cara Cara, and others. 

You have two options regardless of the cultivar you select. You can either add a scion variety (orange cultivar) to the rootstock or purchase a budded or grafted plant from the nursery.

When to bring citrus trees indoors?

Simply add the scion variety via T-budding when your rootstock is one year old, and then tie them until the successful union. After three to six months, move this plant to a larger pot with a 4×2 ft dimension and care for it. Everything else has already been mentioned.