Please check this PDF attachment.

Thank you Nirmala and Arvind for your valuable suggestions. I have read them all. As I can see, most of the literature have peat as a common ingredient  for the pot culture- which is organic in nature and contain undefined amount of nutrient compounds. Peat therefore is not suitable for my experiment as the mandate is to use an inert substrate  (especially for macronutrients like N, P) for plant growth, meant  to be supplemented by external source of nutrition (completely defined). In this backdrop, I am looking for an useful composition that is capable of retaining the nutrients (when added through nutrient solution), yet at the same time facilitates aeration and drainage . Is Vermiculite:peat:horticulture grade sand ans option?

Many thanks.

Please do not overlook the microbial component ( especially the microbial consortium in broth mode)  to do some more value addition to the substrate , you are looking at ...plants will perform far better than without it ...

Dear Dr.Bandyopadhyay,Scientists also used Hewitt(1966) solution  in nutrient or sand culture.Your vermiculite and perlite medium may be similar to sand culture.From my own experience and observation of some students' work in my early career,there are three problems with nutrition in sand culture- Nitrogen may be inadequate.Sometimes iron availability is a problem in  cereals or millets and also the precipitation of some nutrient ions especially the micronutrients.It is better to prepare micronutrient stock solution separately and apply after necessary dilution.I used Hewitt solution in my studies.You may find the details of Hewitt solution in the following paper.

The effect of different nutrient solutions on some growth indices of greenhouse cucumber in soilless culture.Ghehsareh,A.M. Khosravan,S. and Shahabi,A.A.Iournal of Plant Breeding and Crop Science 3 (12) 321-326.

www.academicjournals.org/journals/JPBCS/article-full-text.pdf/B83FEDF9559

You may also see the following researchgate link.

https://www.researchgate.net/post/Can_anyone_advice_a_good_nutrient_solution_for_cereals_grasses

Millets are aridity loving crop and needs less water and frequency of irrigation (1-3 light irrigation depending upon crop and soil). These crops are grown under rainfed conditions in arid and semiarid agroclimate. Whenever we grow them under greenhouse conditions, internal microclimate is changed, there will be high  humidity which is not desired and we frequently irrigate which is not needed. if you grow in green house you will get vegetative growth initially but plants will become diseased and even grain formation will not be satisfactory.

Thank you Dr. Rao and Malhotra.

@Dr Rao. I am using concentrated stocks(prepared separately) of Hoagland and applying them at half the strength to plants in final nutrient solution.  I shall consult Hewitt solution and get back to you. Moreover, I am irrigating the plants after every 72 hours.Thanks

@Dr. Malhotra. I am trying to grow the plants in a more rigid condition like growth chamber wherein I can simulate very arid conditions with less humidity. Greenhouse conditions have been adjusted to millets growing conditions but I agree that they may not be tightly controlled. The limitation with me is that I cannot grow them in field and soil since I should be able to know the concentration of N I am provisioning to the plants under an universally constant growing condition for more than 200 genotypes. Moreover, what according to your opinion should be the irrigation regime. I am using half strength hoagland (ph 6.5-6.8) after every 72 hours for millets?

Many thanks.

Nice discussion friends. Here are are certain dos and donts while experimenting such studies: 

* Avoid compaction of growing media. Containers should be lightly filled and the excess brushed off the top. Do not stack growing containers or pre-fill them too far in advance.

* Add water to peat-based mixes before filling plug trays to help create more aeration.

*Test the media pH, electrical conductivity and wettability before use.

*Do not make changes to your current growing media without experimenting first to see if changes may affect your cultural practices.

*If mixing your own media, thoroughly mix components, but do not over-mix, especially if a media contains vermiculite or controlled release fertilizer.

*Do not store media that contains fertilizer especially if the media is moist.

Avoid contamination of components for finished media by keeping amendments in closed bags or by covering piles.

*Avoid contamination of bagged commercial media by keeping any broken bags covered.

*It is advisable to wear a dusk mask when handling dry peat moss or vermiculite to avoid inhaling these materials.

*Use surfactants occasionally to assure rapid wetting of the media.

Growing media consist of mixtures of components that provide water, air, nutrients and support to plants. The media provide plant support, while the nutrients are provided by added fertilizers. Water and air are provided in the pore spaces in the media. Four main factors affect air and water status in containers: the media components and ratios, height of the media in the container, media handling and watering practices. Only a portion of the water added to media is available for root uptake. Another important characteristic of media components that influences watering practices is wettability, i.e., the ability of dry media to rapidly absorb water when moistened. A surfactant used occasionally can help media rewet more readily. The choice of media should be influenced by irrigation systems and practices.

Some thoughts ....

Thank you Dr. Srivastava! Indeed very useful guidelines for my experiment.

Some more thoughts....

Hewitt (1966) lists over 150 such solutions which vary widely in their

composition, nitrogen source and total nutrient concentration. These solutions

have largely been developed empirically, and for the most part without the benefit of precise information regarding optimum nutrient concentrations or combination of nutrients for growth of particular species (Asher, 1977). It is generally accepted that the external concentration of nutrients required to satisfy the internal demands of plants differs between species. Consequently there can be no single nutrient solution which would be expected to ^ive satisfactory results under all circumstances. Nevertheless some solutions such as the Long Ashton and the Hoagland solution are widely used and are considered to be suitable for supporting growth of a range of different plant species (Hoagland and Arnon, 1950; Hewitt, 1966). However, assessment of the suitability of the nutrient solutions listed by Hewitt (1966) for obtaining maximum growth of pasture and crop plants is made difficult since few detailed comparisons have been made between the effects of solutions on the growth and chemical composition of such plants.

Excerpts from Hewitt et al ( 1983, New  Phytol. 94: 537-548) comparing as many 8 growing media for crops like ryegrass, maize , white clover , but maize was most  affected with Fe-deficiency...