AL Landscape cheat sheet

Bubble diagrams precede schematic plans: they map functional zones and circulation before any dimensional design is drawn.

The design process sequence is site inventory and analysis, program development, schematic design, design development, construction documents, then bidding and construction observation.

A site inventory records topography, soils, drainage patterns, sun and wind exposure, existing vegetation, views, and utilities before any design decision is made.

Scale ratios: 1:10 shows detail planting, 1:50 to 1:100 shows site plans, 1:500 and smaller shows master planning.

Human circulation clearances: 0.9 m minimum for a single pedestrian path, 1.5 m for two people passing, 1.2 m for a wheelchair turning space.

The rule of thirds and golden ratio (about 1.618) are proportion tools for locating focal points and dividing spaces.

Hierarchy in plan is expressed through path width, paving material change, and planting mass, not through signage alone.

A program statement lists required spaces, quantities, and performance criteria before form-making begins; it is the client brief translated into design criteria.

Hardiness zones reflect average annual minimum temperature; heat zones reflect days above 30 C, and both must be satisfied for reliable plant performance.

Right plant, right place: match the plant's mature height, spread, root volume, light requirement, soil pH, and moisture regime to the actual site conditions.

Soil pH controls nutrient availability: iron and manganese become deficient above pH 7.5, and phosphorus locks up below pH 5.5.

Planting density rule: space plants at roughly half to two-thirds of their mature spread to allow canopy closure without overcrowding.

Nursery stock grades: bare root, container-grown, and balled-and-burlapped; B&B stock loses a substantial portion of its root system and needs establishment care.

Succession and layering: canopy trees, understory trees, shrubs, herbaceous perennials, and groundcover form a vertical structure that suppresses weeds and supports habitat.

Alleopathy example: juglone from Juglans nigra (black walnut) inhibits growth of many ornamentals within the root zone.

Xeriscape principles: appropriate zoning of turf, soil improvement, efficient irrigation, mulching, and limited turf area reduce water demand.

Concrete mix for paving is typically 1:2:4 (cement:sand:aggregate) by volume; a 28-day compressive strength of 20-25 MPa suits pedestrian paving.

Concrete expansion joints are spaced at 1.5-3 m and control joints at 1-1.5 times slab thickness to control cracking.

Base course for pedestrian paving is typically 100-150 mm of compacted granular material; vehicular paving needs 200-300 mm.

Compaction of granular base is specified as a percentage of maximum dry density (typically 95%) from a standard or modified Proctor test.

Mortar for stone and brick is typically 1:3 or 1:4 cement to sand; lime is added for workability and flexibility.

Decking joist spacing: 400-600 mm for timber decking boards, with board gaps of 5-8 mm for drainage and expansion.

Retaining walls above about 1 m height generally require engineering design, drainage behind the wall, and a geotextile-wrapped drainage aggregate.

Material takeoff formula: quantity = area x thickness x density; use bulk densities such as concrete 2400 kg/m3, sand 1600 kg/m3, topsoil 1300-1600 kg/m3.

Grading rule: slope away from buildings at a minimum of 2% for the first 3 m to direct surface water away from foundations.

Typical surface drainage slopes: 1-2% for turf and lawn, 1.5-2% for paved walks, 1% minimum for paved surfaces, and 0.5-1% for drainage swales.

Contour lines connect points of equal elevation; contour interval is the vertical distance between adjacent contours, and closer spacing means steeper slope.

Slope formula: percent slope = (rise / run) x 100; a 1:20 slope equals 5%.

Cut and fill volumes are balanced to minimize earthwork cost; the balance point is where cut equals fill and haul distance is minimized.

A swale is a shallow vegetated channel that conveys and infiltrates runoff; a berm is a raised mound used to block views, noise, or water.

Stormwater detention stores runoff temporarily and releases it at a controlled rate; retention holds water permanently.

Runoff volume estimate uses the rational method: Q = C x i x A, where C is the runoff coefficient, i is rainfall intensity, and A is area.

Sprinkler head spacing follows head-to-head coverage: spacing equals the throw diameter so each head reaches the adjacent head.

Application rate in mm/hr = (flow rate in L/hr) / (area in m2); it should not exceed the soil infiltration rate to avoid runoff.

Drip irrigation operates at 50-150 kPa and delivers 1-4 L/hr per emitter, applying water directly to the root zone.

Irrigation zones should group plants by water need, sun exposure, soil type, and sprinkler type; turf and shrubs belong on separate valves.

A rain sensor or soil moisture sensor overrides the controller and is required in many water-conservation codes.

Distribution uniformity measures how evenly water is applied; low uniformity means overwatering in wet spots and stress in dry spots.

Reference evapotranspiration (ETo) times a crop coefficient (Kc) gives plant water use: ETc = ETo x Kc.

Backflow prevention is mandatory on any irrigation system connected to a potable supply; an atmospheric vacuum breaker or reduced-pressure zone assembly is used.

Mowing height rule: never remove more than one-third of the leaf blade in a single cut; mow higher in summer heat stress.

Pruning timing: prune spring-flowering shrubs after bloom, and summer-flowering shrubs in late winter or early spring before new growth.

Fertilizer application rate is expressed as kg of nitrogen per 100 m2 per year; the N-P-K label gives the percentage of each nutrient by weight.

Fertilizer calculation: kg of product = (desired kg N) / (percent N in product).

Mulch depth of 50-75 mm suppresses weeds, conserves moisture, and moderates soil temperature; keep mulch clear of trunks to prevent rot.

Integrated pest management (IPM) sequence: prevention and cultural controls first, then biological, then targeted chemical as a last resort.

Turf renovation includes aeration, dethatching, overseeding, and topdressing; core aeration relieves compaction and improves infiltration.

A maintenance schedule is organized by season and task frequency: weekly, monthly, seasonal, and annual.

The three pillars of sustainability are environmental, social, and economic; a sustainable design must satisfy all three.

Stormwater best management practices (BMPs) include rain gardens, bioswales, permeable paving, green roofs, and cisterns.

Low-impact development (LID) manages rainfall as close to its source as possible through infiltration, storage, and evapotranspiration.

Native and locally adapted plants reduce irrigation, fertilizer, and pesticide inputs and support local pollinators and wildlife.

Life cycle assessment (LCA) evaluates environmental impacts from material extraction through disposal; embodied carbon is the CO2 emitted in producing a material.

Soil organic matter improves water-holding capacity, structure, and nutrient cycling; compost amendment is a primary soil-health strategy.

Water conservation strategies include drought-tolerant planting, efficient irrigation, rainwater harvesting, and reducing turf area.

Green infrastructure provides ecosystem services such as cooling, air filtration, carbon sequestration, and habitat, which can be quantified and credited.

Overhead is indirect cost (office, insurance, equipment) not tied to a specific project; profit is a separate markup above cost.

Markup is applied to cost; margin is profit as a percentage of the selling price. Margin = markup / (1 + markup) and markup = margin / (1 - margin).

Labor cost = crew hours x hourly wage x a labor burden factor (typically 1.3-1.6 for taxes, insurance, and benefits).

Quantity takeoff: measure lengths, areas, and volumes from drawings, then apply unit costs to obtain a cost estimate.

Contingency of 5-10% is added to estimates to cover unknowns; larger for early-stage or high-risk work.

A change order documents scope changes, their cost, and their schedule impact, and must be approved before work proceeds.

A critical path is the longest sequence of dependent tasks; any delay on the critical path delays the whole project.

Cash flow management tracks when money is received versus spent; progress payments and retainage affect project liquidity.