Potato (Solanum tuberosum L.) is considered one of the ideal staple foods for HFG due to its numerous merits. These include: (1) high harvest index, (2) high tuber production, (3) starchy tubers providing ample nourishment, (4) uncomplicated cultivation requirements, (5) adaptability to environmental stresses and low soil fertility, (6) relatively long shelf life, (7) simple food processing demands, and (8) asexual propagation through tubers for steady nutritional component regeneration (Wiersema and Booth, 1987; Coffin et al., 1993; Boivin et al., 2020; Devaux et al., 2021; Liu et al., 2021). Domestic potted potatoes are shown in Figure 1.

Potato is an important food security crop and has long been regarded as a “super food” (Devaux et al., 2021). In the science fiction film “The Martian”, the protagonist, an astronaut and botanist played by Matt Damon, grows potatoes to survive on Mars. This fictional scenario is now becoming a potential reality. Chinese scientists have been dedicated to biotechnological advancements in space agriculture and have proposed the Whole-Body Edible and Elite Plant (WBEEP) strategy for potato improvement. This strategy aims to address the inherent problem of toxic solanine in potato plants, specifically in the aerial portions such as stems, leaves, and berries, which are currently inedible (Liu et al., 2021). On the basis of genetic modification that can block the biosynthesis of solanine, the WBEEP-potatoes, whose whole bodies are edible, might be created in the future and subsequently applied in HFG.

Tomato (Solanum lycopersicum L.), a staple of Italian and Latino cuisines, enriched with essential nutrients and bioactive antioxidant compounds, has become a worldwide vegetable (or fruit, as some insist) (Perveen et al., 2015). Statistically, in the United States, among all HFG vegetables, tomato is the most popular one (Cruz et al., 2023). Non-miniature tomatoes with indeterminate growth characteristics require the application of plant growth regulators (e.g., paclobutrazo) to achieve compact potted plants for HFG (Melo et al., 2018; Cruz and Gómez, 2022). In comparison to non-miniature counterparts, dwarf or miniature tomatoes (Figure 2) have smaller plant canopy diameters, shorter internodes, and pedicels. These features offer several advantages, including strong resistance to lodging damage, suitability for diminutive space, and the absence of pruning requirements, which are crucial for HFG (Melo et al., 2018; Zhao et al., 2023). Several dwarf and semi-dwarf tomato varieties with well-proportioned plant architectures and eaten fruits, such as “Micro Gold” (Zhao et al., 2023), “Micro Tom” (Ke et al., 2022), “Red Robin” (Richardson and Arlotta, 2022), “Sweet ‘n’ Neat” (Richardson and Arlotta, 2022), “Terenzo” (Richardson and Arlotta, 2022), “Tiny Tim” (Richardson and Arlotta, 2022), and “Tumbler” (Richardson and Arlotta, 2022), have been developed as HFG tomato varieties. In addition, a study demonstrated that “Terenzo” and “Tumbler” achieve the highest yield, while “Micro Tom” is the least productive variety among six dwarf tomato cultivars, including “Micro Tom”, “Red Robin”, “Sweet ‘n’ Neat”, “Terenzo”, “Tiny Tim”, and “Tumbler” (Richardson and Arlotta, 2022).

Leafy vegetables have a short growth cycle and are essential sources of required vitamins and minerals for human beings (Yoon et al., 2017). Figure 3 illustrates the abundant options of leafy vegetables used for HFG. As a layperson-friendly vegetable, romaine lettuce (Lactuca sativa L. var. longifolia) grows fast and can easily be cultivated in human settlements using soil culture, substrate culture, or hydroponics (Majid et al., 2021; Noh and Jeong, 2021). A handful of leafy vegetables used for spices are also suitable for HFG, for instance, basil (Ocimum basilicum L.) and rosemary (Rosmarinus officinalis L.) (Aditya and Zakiah, 2022; Kim et al., 2022). Basil, also referred to as “more precious than gold” or “nine-storey tower” in China, is the main ingredient of Chinese cuisine such as Three Cup Chicken and Italian Pesto sauce (Tanzilli et al., 2023), and rosemary is routinely used for shish kebabs and beef steaks.

Sprouts (i.e., microgreens), a novel class of edible veggies harvested and consumed at an immature stage (Teng et al., 2023). As shown in Figure 4, with small plant sizes, sprouts are advantageous when planted in tiny balcony, kitchen windowsill or other compact places because of their better spatial efficiency (Teng et al., 2023). Additionally, sprouts are non-polluting green foods produced directly from seeds, have no intricate cultivation demands, and can be grown in soil or hydroponically in both light and dark environments (Reed et al., 2018; Le et al., 2021; Xiao et al., 2022). Healthwise, as functional edibles with anti-oxidant powerhouse credited with preventing some diseases, sprouts deliver richer nutrition than seeds, since they contain high levels of carbohydrates, dietary fibers, amino acids and health-beneficial metabolites like polyphenols (Zhang et al., 2022; Nolasco et al., 2023; Suathong et al., 2024; Zhao et al., 2024). Moreover, nutrient-rich food sprouts have been found to grow faster and can be harvested earlier compared to other vegetables. This quality makes them particularly valuable during times of major disruptions in the fresh product supply chain, as they effectively ensure the intake of required vitamins (Reed et al., 2018; Zhang et al., 2022). Hence, sprouts have captured more attention from HFG hobbyists with health consciousness (Supapvanich et al., 2019; Gilbert et al., 2023).

Traditional legume seed sprouts, such as pea sprouts (Pisum sativum L.), are widely consumed and highly popular in various regions around the world. They are particularly favored in Southwest China, including Sichuan Province and Guizhou Province, as well as in several Asian countries like Japan, Korea, and Thailand. This popularity can be attributed to their desirable qualities, including crispness, tenderness, fresh fragrance, and significant nutritional value (Lin et al., 2023; Suathong et al., 2024). In recent years, plentiful novel sprouts with functions differed from legume seed sprouts are emerging, such as the broccoli sprouts rich in glucosinolates and sulforaphane (Guo et al., 2016), the coriander sprouts rich in phylloquinone and tocopherols (Rajan et al., 2019), and the rapeseed sprouts rich in glucosinolates and selenium (Xiao et al., 2022), the presence of these sprouts greatly expands the choices for HFG, and provides urbanite with more comprehensive nutrition.

Fruits are an important component of the human daily diet, but HFG fruits available are obviously few compared with vegetables. Strawberry (Fragaria × ananassa Duch.), a perennial herb, cultivated worldwide due to the vibrant color, fragrant flavor, succulence, distinctive sweetness, high nutritional value (e.g., rich in minerals, vitamins, anthocyanins, carotenoids, and polyphenols) and health benefits, is ideally suited for HFG owing to their small size and relatively lower light requirements (Tulipani et al., 2011; Battino et al., 2021; Hardigan et al., 2021; Martín-Pizarro et al., 2021; Wang et al., 2022; Avendaño-Abarca et al., 2023; Zheng et al., 2023; Liu et al., 2024). Domestic potted strawberry cultivation is shown in Figures 5A,B. The trend of HFG opens a novel dimension to strawberry cultivation (Olbricht et al., 2014). Besides common white-flowered strawberries, there are also red-flowered and pink-flowered varieties that have been developed through distant hybridization (Fragaria × Potentilla), which have gained popularity among urban gardeners for their use in landscaping and potted viewing (Ding et al., 2019; Liu et al., 2021). A pink-flowered strawberry cultivar is shown in Figures 5C,D. As eye catchers, the red-flowered and pink-flowered strawberries with unique flower morphological characteristics (e.g., semi-double flowers in succession), diverse petal colors (i.e., covers the whole red series, flower colors range from light pink to deep red), relatively long florescence, strong ability to reproduce, edible and ornamental values are “add flowers to the brocade” for HFG, commanding a markedly higher selling price and economic value distinguished from common white-flowered strawberry varieties (Xue et al., 2016; Ding et al., 2019; Xue et al., 2019; Guan et al., 2023). Actually, there is an immense market potential for ornamental strawberries in the post-epidemic era (Guan et al., 2023).

With a history of over 60 year efforts in modern ornamental strawberry breeding, breeders have successfully developed a broad assortment of pink-flowered and red-flowered strawberry cultivars with independent intellectual property rights (Mabberley, 2002; Khanizadeh et al., 2010; Xue et al., 2015; Ding et al., 2019; Bentvelsen and Vange, 2021; Yue et al., 2022; Guan et al., 2023). For instance, ABZ Seeds, a Dutch breeding company dedicated to the development of F1 hybrid seed-propagated strawberry cultivars, has delved into ornamental strawberry breeding and released a series of superior ornamental strawberry varieties full of aesthetic morphological attributes, such as “Summer Breeze Cherry Blossom”, “Summer Breeze Rose”, “Gasana” and “Toscana” in the market (Bentvelsen and Bouw, 2006; Bentvelsen and Vange, 2021). Table 1 provides an overview of the some institutions involved in ornamental strawberry breeding and the varieties they have developed.

Plant growth and development are significantly influenced by light since it has an impact on the energy metabolism of plants. Insufficient exposure to light during plant growth hinders carbon dioxide (CO₂) absorption and assimilation, which lowers photosynthetic efficiency and impacts agricultural productivity (Deng and Deng, 2018). However, a typical issue in HFG is inadequate lighting, especially on low-rise balconies where low-intensity scattered light is the norm, thus light supplementation is very important. Traditional light supplementation devices are considerably power-consuming. Daylight harvesting is a technique extensively utilized in protected agriculture, which can effectively modulate supplemental lighting been based upon sunlight (Bhuiyan and van Iersel, 2021). Some individuals interested in new things opt for high-end automated machines equipped with advanced features such as plant lighting devices with daylight harvesting capabilities. These devices have an intelligent adjustable light function that emits supplemental light based on photosynthetic active radiation. They are particularly useful for HFG plants that are typically deprived of sunlight in balconies or other areas. For instance, a novel micro indoor smart hydroponics system, named Adpatalight, utilizes Internet of Things (IoT) technology. This system harvests ambient light by utilizing an inexpensive AS7265x IoT sensor to measure photosynthetic active radiation, resulting in a significant reduction in energy consumption (Stevens et al., 2022).

Soil-based HFG may pose a contamination risk due to urban soil, besides, low fertility, low organic matter, decreased activity and diversity of soil organisms, as well as high concentrations of stones, gravels, and artifacts are frequently found in urban soils. These elements may have a detrimental effect on horticultural crop productivity, rendering urban soils unsuitable for HFG, therefore, utilizing inert and clean substrates is an effective solution (Ercilla-Montserrat et al., 2018; Izquierdo-Díaz et al., 2023). Spanish researchers found that the output of a open-air rooftop soilless home food garden based on perlite bag culture, can achieve a high degree of self-provisioning for a two-member household (Boneta et al., 2019). Now in China, there are some substrate-based vertical system used for HFG, two of them are shown in Figure 6.

The discrepancy between hydroponics and traditional cultivation is that hydroponics has no demand for plowing field and weeding, also, it can reduce even eliminate the application of pesticides, making HFG more feasible and convenient in urban settings where space is limited (Solis-Toapanta et al., 2020; Noh and Jeong, 2021). In actuality, hydroponic systems include aeroponics, wick watering, DWC (Deep Water Culture), DFT (Deep Flow Technique), NFT (Nutrient Film Technique), and more. The wick watering system is the most basic and low-maintenance of all the hydroponic systems. Because of this, it works well for small plants like lettuces and strawberries and is therefore more appropriate for HFG. Furthermore, hydroponics combined with a vertical system can achieve higher yield of leafy vegetable production in a compact space (Rajan et al., 2019), two hydroponic systems are shown in Figure 7. In a recent development, Malaysian scientists have introduced a smart hydroponic system called SMART GROW, which utilizes Internet of Things (IoT) technology. This system offers several advantages, including minimal space requirement, cost-effectiveness, automated water level regulation, and the ability to cultivate various edible plants at home (Shin et al., 2024).

Aquaponics, considered as a bio-integrated system mimicking a complex ecosystem, is composed of beneficial bacteria (e.g., heterotrophic bacteria and nitrifying bacteria), recirculating aquaculture and hydroponic cultivation (Wongkiew et al., 2017). This environmentally friendly system utilizes the nitrogen in aquaculture effluent as nutrients for hydroponic plant growth. At the same time, the plants purify the water, creating a suitable environment for the culture of aquatic animals such as pearl gourami (Trichogaster leerii), carp (Cyprinus carpio), tilapia (Oreochromis mossambicus), catfish (Clarias gariepinus), and shrimp (Litopenaeus vannamei). By combining these elements, aquaponics effectively addresses the individual limitations of each component (Makhdom et al., 2017; Wongkiew et al., 2017; Pineda-Pineda et al., 2018; Goddek and Keesman, 2020; León-Cañedo et al., 2023). Aquaponics has gained rapid development and wide application in home food production due to its high resource utilization rate, absence of chemical fertilizers and antibiotics, low consumption, high efficiency, and sustainability (Kyaw and Ng, 2017; Wongkiew et al., 2017; Li et al., 2018; Suárez-Cáceres et al., 2021). A study has shown that aquaponics can provide equal or higher nutrient content for lettuce compared to traditional hydroponics. Additionally, the highest lettuce yield was achieved when treating with 120% of the recommended fish diet (Pineda-Pineda et al., 2018).

A smart aquaponics system has been designed and developed by scientists in Singapore for HFG. The system is primarily used for producing water spinach and raising tilapia (Kyaw and Ng, 2017). Equipped with various sensors, actuators, microcontrollers, and microprocessors, the system is able to monitor and regulate water quality, light intensity, and aquatic animal feed (Kyaw and Ng, 2017). If any abnormal system state is detected by the sensors, the user will automatically receive early warnings from the system, and the actuators will rectify the abnormal conditions without any human intervention (Kyaw and Ng, 2017). The dispensing of aquatic animal feed is done according to the user’s preset timings (Kyaw and Ng, 2017). The extent of self-provisioning in aquaponic systems is heavily dependent on their size. In the past, achieving a high degree of self-sufficiency from a small-scale aquaponic system was considered nearly impossible due to space constraints and limited productivity. However, recent advancements have led to significant progress in this area. Researchers in Spain have successfully developed two micro-scale domestic aquaponic systems, which consist of a 4.56 m² cropping area and a 1 m³ fish tank. Excitingly, the results of their study demonstrated that these home-based aquaponic systems can annually produce 62 kg of tilapia and 352 kg of 22 different agricultural products, including tomatoes, peppers, melons, pumpkins, cucumbers, basil, broccoli, cabbage, Chinese cabbage, onions, chard, and lettuce (Suárez-Cáceres et al., 2021). The output can provide self-sufficiency along with dietary diversity for a four-member household throughout the year (Suárez-Cáceres et al., 2021). Compared to other cultivation patterns like the rooftop system mentioned earlier, aquaponics is more likely to have higher productive efficiency in supporting self-provisioning (Boneta et al., 2019).

Paper-based sprout garden is a system suitable for home-grown sprout production, it is based on a piece of absorbent paper with watering at regular intervals and can harvest after 10 to15 days of growth given the optimum environments. At present, there are multifarious grow plates and racks available for picking on the basis of spatial layout of residence (Li et al., 2023). Additionally, for those new to sprout cultivation, user-friendly microgreen growth kits like the one introduced by Hamama, Inc. are also recommended options (Teng et al., 2023).

The constituents of the nutrient solution have a significant impact on the yield and quality of hydroponic crops. Ssamchoo (Brassica lee ssp. namai cv. Ssamchoo) is a vegetable commonly used in Ssam, a Korean specialty food. However, cultivating Ssamchoo hydroponically poses challenges due to its sensitivity to the composition and concentration of the nutrient solution (Noh and Jeong, 2022). A research reported that nutrient solution (the ratio of NO₃⁻ to NH₄⁺ to urea is 50: 25: 25) combined with silicon (10.7 mmol L⁻¹) is suitable for planting Ssamchoo in a household hydroponic system. This optimized nutrient solution not only allows for achieving the highest yield but also effectively mitigates the harmful effects of ammonium on Ssamchoo (Noh and Jeong, 2022).

High-quality soils are often not readily available in urban residential areas. In addition, soilless substrates used for HFG typically lack sufficient nutrients. Therefore, it is essential to enhance soil fertility and functionality by applying some fertilizers, such as chemical fertilizers, homemade composts or commercial organic fertilizers (Lal, 2020; Shrestha et al., 2020; Dorr et al., 2023). For cutbacks in expense of chemical fertilizers and organic composts used for HFG, many urban gardeners opt to prepare small-scale home composts themselves (Gao et al., 2022). Biodegradable kitchen waste, such as meat or fish scraps, and urban green waste, such as fallen leaves and chopped grasses, can be transformed into valuable assets through the production of home-made composts. This practice aligns with the principles of a circular economy and sustainable agriculture (Storino et al., 2016; Hou et al., 2024).

Effective Microorganism (EM), originated from Japan, is one of the useful additives for composting (Fan et al., 2018). A research revealed that the practice of home-scale composting inoculated with the activated EM, is able to significantly reduce the smelly odor during the decomposition, promote humification of raw composting materials, as well as increase the decomposition rate of fat (Fan et al., 2018). In another study, it was found that regular urban gardeners were able to effectively compost kitchen waste indoors by adding EM and lime at a rate of 1% of the wet weight of the feedstock. This homemade compost also led to improved seed germination for most families (Gao et al., 2022). Bacillus thuringiensis (Bt) is a pathogen with potent pesticidal activity (Jurat-Fuentes et al., 2021). More recently, Spanish researchers have presented an approach to produce Bt-enriched home-scale compost through an uncomplicated procedure and low-input process (Ballardo et al., 2020). The efficiency of home composting also need to be focused on. A study demonstrated that a period of 12 to 15 months may be suitable for the development of home composting (Tatàno et al., 2015). However, another research reported that it only takes 21 days to convert food wastes to composts just with minor alkalinity (Margaritis et al., 2023). The discrepancy between these two studies could be attributed to the varied additives used.

Actually, compare to time-consuming composting, there is a more efficient approach to kitchen waste treatment—black soldier fly larvae-based composting (Nguyen et al., 2015). Black soldier fly (Hermetia illucens L.) is an insect commonly utilized for the bio-conversion of kitchen waste. Its larvae efficiently convert various organic wastes into nutritious insect proteins and fats, while also reducing the content of antibiotics and decreasing the abundance of resistance genes commonly found in ordinary home-produced composts (Liu et al., 2017; Cai et al., 2018; Liu et al., 2020). As a fat-rich and protein-rich feed source, black soldier fly larvae can be used for feeding aquatic animals if small-scale aquaponic systems are already equipped in the residence (Qiu et al., 2023).

Regulating photoperiod and temperature can be beneficial for urban gardeners in effectively controlling the growth and harvest time of HFG plants. According to Korean scientists, for romaine lettuce (Lacteal sativa L. var. longifolia), a temperature setting of 25/18°C together with a photoperiod of 14 h were the most suitable for hastened growth. On the other hand, a temperature of 20/15°C combined with an 18 h photoperiod was deemed suitable for delayed growth (Noh and Jeong, 2021).

While it is advisable to minimize the use of chemical agents, it is crucial to apply them judiciously in order to achieve high yields and ensure the safety of harvested produce in HFG systems (Gilbert et al., 2023). For instance, employing safe chemicals such as dilute domestic bleach (0.6% sodium hypochlorite) and freshly generated hypochlorous acid (800 ppm chlorine) for seed disinfestation practices can effectively suppress seed-borne bacterial and fungal infections, thereby preventing food contamination (Ding et al., 2013; Gilbert et al., 2023).