# Evaluation of Biochar and Composit Mixes as Substitutes to a Commercial Propagation Mix  
[PERSON]  
1 Institute of Urban Agriculture, Chinese Academy of Agricultural Sciences, Chengdu 610000, China; [EMAIL_ADDRESS]  
[PERSON]  
2 Department of Horticultural Sciences, Texas A&M University, College Station, TX 77843, USA; [EMAIL_ADDRESS]  
[PERSON]  
33 Department of Horticultural Sciences, Texas A&M Agri  
production adds extra value to the bioenergy process [19]. Research has shown the potential of BC to be used in seed propagation substrate for agricultural production [20]. It was shown that coconut shell BC (5%, 10%, 20%, or 40%, by volume) could be mixed with an adapted cornell seed germination mix and did not affect final germination percentages [21]. Additionally, the rate of BC incorporation, base substrate, and the plant species all have effects on the final seed germination and seedling growth. [PERSON] et al. [22] showed tomato (_Solanum Lycopersicum_) seed germination and plant growth were higher in peat mixes with 10% woodchips BC than those in mixes with 50% BC. Similarly, [PERSON] et al. [23] evaluated the softwood BC substitution for peat in a 70:30 (v/v) peat:perlite mixture on marigold (_Tagetes erecta_) seed germination and seedling growth. They concluded that mixes with high BC substitution rate (50%, 60%, or 70%, by vol) had lower germinations than the mixes with low BC rates (0, 10%, 20%, 30%, or 40%, by vol) with all substrate pHs adjusted to 5.8. Compared to the 70:30 (v/v) peat:perlite mixture, mixes with 10% or 70% BC led to lower plant height while mixes with 20%, 30%, 40%, 50%, or 60% BC had no effect. [PERSON] et al. [24] also pointed out that the lower germination rate and plant height of water spinach (_Ipomoea aquatic_ Forsk) were found in substrates with more wheat straw BC, and that the seed germination rate and plant height in substrates with 16% (by volume) BC with 0.8 g L\({}^{-1}\) super absorbent polymer were higher than the substrates without super absorbent polymer, indicating that both the BC incorporation rate and base substrate affect seed germination and seedling establishment. [PERSON] et al. [25] showed that five different seeds, including lentil (_Lens culinaris_ Medikus cv. Pardina), cress (_Lepidium sativum_), cucumber (_Cucumis sativus_ cv. Wisconsin SMR-58), tomato (cv. Alicante), and lettuce (_Lacuca sativa_ cv. Great Lakes) seeds had different responses to three different BC mixes prepared from wood, paper sludge plus wheat husks, and sewage sludge. Therefore, the impact of substrates amended with BC on seed propagation and plant growth had been variable. Mixes with high percentages of BC tend to have less positive effects on seed germination and seeding growth compared to those with low percentages. However, the hardwood BC was suitable to be used as container substrates to grow plants. Research has shown positive results for using a high rate (80%, by volume) of the hardwood BC with composts when growing tomato and basil (_Ocinum basilicum_) in containers [26; 27]. It may be suitable as a propagation mix at a high rate, if incorporated with substrate components with fine textures, such as composts. Composts are valuable alternative components for soilless substrates. Composing and vermicomposting are generally considered as environmentally-friendly and sustainable management processes to recycle plant or animal organic wastes [28]. Vermicompost (VC) is the end product of using earthworms to degrade organic wastes [29; 30], which has fine particulate structures and a lot of nutrients [31; 32]. Biochar mixes with VC may increase nutrient retention and have a positive impact on plant growth [7]. Chicken manure compost (CM) is also fine-textured and is cheaper than VC. Properly treated CM could have nutrients readily available to plants [33; 34]. Most research testing the effect of BC in germination substrates usually choses to use BC to substitute certain percentages of the commercial propagation mix.