Maize rewards being early and punishes being late, but planting into rain that turns out to be a false start wastes seed you may not be able to replace. Judging the difference is the first skill of the season.
Has the season actually started?
A single heavy shower is not the season. What you are waiting for is rain that has wet the soil to a good depth and been followed by more within a few days. Dig down a hand span: if the soil is damp all the way, the rains have arrived. If only the top is dark and it is dry underneath, wait.
Planting into a false start means germinating seed into soil that then dries, and a stand that comes up patchy and never recovers.
Prepare before the rain, not after
Land opened during the dry season, so that residues have broken down and clods have weathered, can be planted immediately when the rain comes. Land still unopened when the rain arrives costs you two or three weeks at exactly the point where those weeks are worth the most.
Spacing
Widely used spacing for a pure maize stand is about 75 cm between rows and 30 cm within the row, one plant per station after thinning. That is roughly 44,000 plants per hectare and is a reasonable default for most improved varieties.
Two practical points matter more than the exact figure. Straight, evenly spaced rows make weeding much faster, and faster weeding means it actually happens on time. And thinning to one plant per station beats leaving two to compete, even though it feels wasteful.
Plant about two to three fingers deep. Too shallow and the seed dries or is taken by birds; too deep and emergence is weak and uneven.
The first six weeks decide the crop
Weeds compete hardest while the maize is small and cannot shade them out. A crop kept clean for the first six weeks will usually outyield a better-fertilised crop that was weeded late. If labour is short, weed the maize before anything else in the garden.
Gap-fill within the first week or two of emergence. Later than that, the replacements are so far behind that they contribute little and simply compete.
Seed
Recycled hybrid seed loses vigour and yield noticeably by the second generation. Open-pollinated varieties can be saved with far less loss, which makes them a sensible choice where buying fresh seed every season is not realistic. Choose deliberately rather than by default, and buy from a source you can return to if the seed fails.
Fertiliser
If the soil is exhausted, fertiliser gives a poor return until organic matter is rebuilt. Compost, manure and legume rotation come first; top-dressing worn-out ground is money spent on a problem it cannot fix. Where fertiliser is used, place it beside the plant rather than in contact with the seed.
Related reading: Crops and Farming Guides.