How to Use Canna Terra Professional Plus

Canna Terra Professional Plus is one of the most popular soil mixes for indoor growing in the UK, trusted for its consistent quality and excellent structure. This guide covers how to use it and how to get the best results from your plants.

Written by Will

Using Canna Terra Professional Plus correctly will make a real difference to your results. Canna Terra Professional Plus is the benchmark for premium indoor potting mix — and having recommended it to growers across a wide range of setups, it consistently delivers. Made from a carefully engineered blend of peat moss, tree bark, perlite, and organic ingredients, it creates the exact root environment that fast-growing indoor plants need: excellent moisture retention without waterlogging, strong aeration, stable pH, and a balanced initial nutrient charge. If you’re growing in containers indoors or in a polytunnel, this is one of the best-performing substrates available.

What Makes Canna Terra Professional Plus Different?

Not all peat-based potting mixes are equal — and the quality difference becomes very clear when you’re pushing plants hard under artificial lighting or with intensive liquid nutrient programmes. Canna Terra Professional Plus is formulated specifically for high-performance indoor growing, not general garden use. The key characteristics that set it apart:

• Peat moss: Provides consistent moisture retention and a stable, slightly acidic base pH that suits most indoor crops
• Tree bark: Adds structure and prevents compaction — the mix retains its open, airy texture throughout the growing cycle rather than collapsing around roots
• Perlite: Creates air pockets in the root zone, ensuring oxygen availability even when the medium is well-watered
• Organic ingredients: Support microbial activity and provide a slow-release nutrient base for the early stages of growth

The result is a moisture-to-oxygen balance in the root zone that’s very difficult to replicate by mixing your own media from scratch. Roots receive enough water between feeds, but never sit in saturated, oxygen-depleted conditions.

How to Use Canna Terra Professional Plus

There’s no dosage calculation or preparation required — it’s a ready-to-use growing medium straight from the bag. The process is straightforward:

• Fill your containers with Terra Professional Plus, leaving 5–7cm at the top for watering headroom
• Pre-moisten the medium before transplanting — the mix should be evenly damp throughout, not dry or waterlogged
• Transplant your seedlings, rooted cuttings, or young plants directly into the filled containers
• Water sparingly in the first few days after transplanting — newly transplanted plants don’t need heavy watering until roots begin to establish in the new medium
• Begin liquid feeding once the initial nutrient charge in the medium is depleted — typically after the first 1–2 weeks depending on plant size and growth rate

Container and Pot Recommendations

Canna Terra Professional Plus performs exceptionally well in fabric pots, where the air-pruning effect and enhanced drainage complement the medium’s open structure. Standard plastic pots work well too — just ensure adequate drainage holes. For raised beds and grow bags, use straight from the 50L bag and mix with any existing substrate if needed to improve drainage in heavy clay or dense garden soils.

Watering With Canna Terra Professional Plus

Canna Terra Professional Plus retains moisture well, which means overwatering is possible if you water on a fixed schedule rather than in response to the medium’s actual moisture level. The most reliable method is the lift test: lift your container when it’s freshly watered and note the weight. When it feels significantly lighter — typically 30–40% of its water weight — it’s time to water again. This approach naturally accounts for variation in plant size, temperature, humidity, and growth rate.

For soil-based growing with liquid nutrients, it’s also beneficial to allow slight drying between feeds to encourage roots to spread through the medium in search of water. A good wet-dry cycle produces extensive root networks that make the plant more efficient and productive throughout flowering.

Nutrient Feeding Schedule

Canna Terra Professional Plus contains a starter nutrient charge that will support young plants for the first 1–2 weeks. After this period, begin liquid feeding using a nutrient schedule appropriate for your crop type. For best compatibility, Canna’s own Terra Vega and Terra Flores base nutrients are specifically formulated to work with Terra Professional Plus — but any quality indoor plant nutrient works well.

Typical EC targets for plants grown in Canna Terra Professional Plus:

• Seedling / early veg: 0.8–1.2 EC
• Active vegetative growth: 1.2–1.8 EC
• Flowering: 1.4–2.2 EC (adjust for plant type and feeding response)
• Flush period: Clean water or very low EC flush solution

What Plants Grow Well in Canna Terra Professional Plus?

This medium is genuinely versatile. It performs exceptionally well for:

• Tomatoes, peppers, aubergines, and other fruiting vegetables
• Herbs including basil, coriander, mint, and chives
• Leafy vegetables — lettuce, spinach, chard
• Ornamental flowering plants and houseplants
• Strawberries and other fruiting soft fruits in container growing

Canna Terra Professional Plus vs. Canna Coco Professional Plus

A question we get frequently is which Canna substrate to choose. The answer depends on your system. Terra Professional Plus is the right choice for container-based soil-style growing — pots, fabric pots, raised beds, and grow bags. Canna Coco Professional Plus is the alternative for growers who want a fully inert, buffered coco substrate compatible with hydroponic-style feeding. Coco is better suited to automated irrigation systems and more frequent feeding, while Terra is more forgiving and needs fewer interventions between feeds.

Available Sizes

Canna Terra Professional Plus is available in 50 litre bags. This makes it straightforward to fill multiple containers in a single session. For larger grow rooms with multiple fabric pots or raised beds, the 50L size keeps things efficient without the need to open and mix from several smaller bags.

Frequently Asked Questions

Does Canna Terra Professional Plus need additional perlite?

For most growing situations, no — it already contains perlite as part of its formulation. If you’re growing particularly drought-tolerant plants or want a more free-draining mix for high-frequency automated feeding, you can add up to 20–30% additional perlite by volume. For most crops and hand-watering setups, use it straight from the bag.

What pH should I water with when using Terra Professional Plus?

Target a feed water pH of 6.0–6.5. This range ensures the full spectrum of macronutrients and trace elements remains available in the root zone. Canna Terra Professional Plus has good pH buffering capacity, so slight variations in feed pH are generally corrected by the medium itself.

Can I reuse Canna Terra Professional Plus?

It can be reused, but performance declines noticeably with each cycle. The tree bark and organic components break down over time, reducing the medium’s aeration and water-holding characteristics. For best results, use fresh Terra Professional Plus with each new crop, especially for high-value or long-cycle plants.

Is Canna Terra Professional Plus suitable for outdoor use?

Yes — it works well for outdoor container growing, balcony gardens, and raised beds. Its drainage characteristics are particularly valuable outdoors during heavy rainfall, where denser media can become waterlogged. It’s not necessary for in-ground garden use, where it should be mixed with native soil rather than used as a direct replacement.

Where can I buy Canna Terra Professional Plus in the UK?

We stock Canna Terra Professional Plus in 50L bags alongside the full Canna nutrients range. If you want to run a complete Canna system — Terra substrate, Terra Vega, Terra Flores, and Canna additives — our team can put together a full feeding schedule for your specific setup.

Related Articles

• Nutrients and Additives Guide — complete hub
• The Biobizz Feeding Chart

Further Reading From The Horticulture Company

For more expert growing guides, our nutrients and additives guide explains how to build an effective feed programme, while our LED grow lights comparison and grow tents guide help you optimise your setup. The indoor growing environment guide covers temperature, humidity and CO₂, and the complete UK grow tent guide takes you through setup from scratch.

For authoritative guidance on plant nutrition and health, the Royal Horticultural Society publishes evidence-based growing advice used by professionals and hobbyists alike. Visit The Horticulture Company’s store in Kenilworth, Warwickshire, or browse our full range of products and guides online.