How much water, fertilizer and amendment does this garden need?

Roughly 2 litres — a bit over half a US gallon — during vegetative growth, rising to about 2.4 litres once it is setting fruit and dropping to well under a litre as a seedling. In a container, in full sun and above 90°F, expect to double that, and check the soil rather than trusting any schedule.

Deeply and less often, almost always. Shallow daily watering keeps roots near the surface where they are the first thing to dry out in a heatwave. A deep soak two or three times a week drives roots down and makes the plant far more resilient.

Early morning. Evaporation losses are low, the plant is hydrated before the heat of the day, and the foliage dries in the sun. Evening watering leaves leaves wet overnight, which is exactly the condition powdery mildew and blight need.

Percentage by weight of nitrogen, phosphorus (as P₂O₅) and potassium (as K₂O). A 10-10-10 bag is 10% of each; a 20-5-5 is nitrogen-heavy and intended for lawns and leafy growth. Using a high-nitrogen product on fruiting vegetables gives you an enormous plant with disappointing fruit.

About 30 grams per square metre, which is roughly 6 pounds per 1,000 square feet, split across two or three applications through the season. More concentrated formulations go down at lower rates — the whole point of the higher analysis is that you apply less of it.

Agricultural lime, at roughly 200 grams per square metre for each pH point you want to gain in loam. Multiply by about 0.7 for sandy soil and 1.4 for clay. Work it into the top 6–8 inches, water it in, and allow 2–3 months before you expect the full effect.

Elemental sulfur, around 60 grams per square metre per pH point in loam, with the same texture adjustment. It works only when soil bacteria convert it, so it needs warm, moist soil and time — applying it in cold soil and expecting a result in weeks does not work. Aluminium sulfate acts faster but risks aluminium toxicity and is best avoided in vegetable beds.

Two to four inches on beds. Below two, it does not suppress weeds or hold moisture and simply blows away; above four, it can keep water from reaching the soil at all and stay waterlogged underneath. Keep it pulled back a few inches from trunks and stems.

Multiply the area by the depth in the same units. 200 square feet at 3 inches deep is 50 cubic feet — that is 25 standard 2-cubic-foot bags, or just under 2 cubic yards if you are buying bulk, which is considerably cheaper past about 10 bags.

Because ppm is a derived figure, not a measurement. The meter measures electrical conductivity and multiplies by a scale factor — 500, 640 or 700 depending on the manufacturer’s convention. The same solution reads 700, 896 or 980 ppm on those three scales. Always note which scale a recipe was written for.

Broadly: 0.4–0.8 mS/cm for seedlings and cuttings, 1.2–1.8 for vegetative growth and 1.8–2.4 for flowering or heavy feeders. Above about 2.4 mS/cm you are into root-burn territory for most crops. Species vary enormously, so treat these as starting points and watch the plants.