We are a group of designers, horticulturalist and ecologists who have a shared passion; to turn the grey into the green. 


The Team

Our directors are supported by a team of budding designers, horticulturalists and general green thumbed enthusiasts. 

David Firth FCA


David has over 30 years experience helping companies from start ups to large listed corporates to grow. He has held senior finance positions in companies across a number of sectors including HR consultancy, recruitment, financial markets, IT services, motor retailing and advertising. He is an individual mentor and team developer. 

David is currently a non-executive director of a number of AIM companies. He brings with him strategic planning, corporate governance and broad operational experience to help Meristem flourish.

Habib khan

sales & marketing DIRECTOR


Habib graduated from RICS Surveying background and spent the first part of his life as a surveyor for two of the UK's largest surveying practices, Countrywide Surveyors and GVA Grimley.  

He then decided to move into the sustainability sector and has been instrumental in some of London's landmark schemes.  He has headed up the introduction of Zipcar, the worlds largest car sharing back in 2005, he managed all the regional offices for City Car Club and and was instrumental in introducing the £140m London Bike Sharing scheme currently in London.

He's a keen cyclist and has spent the last 7 years setting up the on-street managed Bike Hangar models across most of London's Local Authorities. His next big challenge is to tackle London Air Quality and to green up London's concrete jungle and create a healthy viable office environment.

He heads up our sales and marketing activities.

david maccoll

operations DIRECTOR


David graduated with a Geography degree with a focus on sustainability and the environment. Following on from this he worked in the sustainability and ethics department for the United Nations World Tourism Organisation in New York and Madrid.

He then returned to London where he has remained in the sustainability sector working for a cycling infrastructure company and living wall business for the last 2 years.

David has a passion for gardening and plants; he heads up our operations team. 

nick day

design & project DIRECTOR


Nick is a qualified landscape designer with an extensive working knowledge of garden design and horticulture. Having led a team of installers and manufacturers for over two decades, Nick's comfortable habitat is being on site and ensuring the project gets delivered efficiently.

With a key interest in biophilia and the vast benefits of which plants give us, Nick's 20 years experience in product design is now focused on designing systems that make it possible for everyone from a home owner to an office dweller to have access to the beauty and benefits of plants.

NIna Simoes

Maintenance Manager | Living Wall Designer


Nina believes passionately in the power of nature to transform urban spaces. In 2016, in parallel with her studies at RHS, she began to design, plant and maintain living walls countrywide, thus deepening her expertise in the developing and inspiring world of green walls. She also leads workshops focused on how plants reduce air pollution and innovative ways in which we can keep urban spaces green.

Nina has a PhD from the University of the Arts, and lectures on the MDes Design Management Innovation course at Ravensbourne.

As a director of environmental documentaries, she has experienced life in the Brazilian Amazon rainforest at first hand, capturing the patterns and compositions of one of the most beautiful forests in the world.

Wilf MacColl

Project manager


Wilf graduated from Newcastle University with a degree in Business Management. He has travelled and worked in Spain, Australia and South East Asia, working in agriculture.

Passionate about the environment, sustainability and nature and is looking forward to a career in helping make London greener. 

He is also an enthusiastic beekeeper and veg grower. 

Jack haslam

Plant Biologist


Jack has a background in plant biology and is interested in how integrating plants into our increasingly urban lifestyles can produce a variety of benefits for cities and their residents. He graduated in 2017 with a bachelor’s in biology and a master’s in plant science from the University of Sheffield, with a year abroad at McMaster University in Canada. He has since worked in green infrastructure in both the UK and Australia, in landscape design and an arboriculture, before taking up his current role at Meristem.

He enjoys using his knowledge of plant biology, as well as his practical skills, to make cities cleaner, happier, and healthier places to live.

Aitor Fernandez


An award winning Design Technician with a 10 year background working for Telecommunications companies, including Vodafone and Telefonica.

Holding a degree in Spatial Design by the University of the Arts London, where he is now often invited back as a lecturer. He focuses on the relation between interiors and exteriors of building environments with a strong sustainable and accessible point of view.

He has huge experience with various CAD applications and is able to produce detailed CAD plans and 3D renders.