"We still have to determine if the fire was deliberately lit."
Mr Glassey said no accelerant was used to start the first fire, but was unsure if accelerant was used to start Tuesday's fire.
Red Star president Gavin Sullivan said they are grateful for PGG Wrightson Seeds Wairarapa donating 200kg of grass seed, enough to cover the entire pitch.
But the Red Star committee is concerned the field may not be re-sown in time for the rugby season, because of water restrictions.
"Water is the only problem at the moment, as we can't irrigate the field," Red Star president Gavin Sullivan said.
"The season is due to start in April, so it's a major worry for us. But the rivers are dry, and there's nothing we can do about that just for now.
"All we need is a bit more rain, and that'll be it."
Despite the dry spell, Mr Sullivan said the seed donation is a "huge weight off [his] shoulders, especially as the fire damage wasn't covered under insurance.
"We're so glad PGG Wrightson could come on board - it's a massive thing they're helping us with.
"As soon the water restrictions lift, we'll be on to the sowing.
"Hopefully, we can start in the next month or so."
The Red Star rugby club has around 200 players from the ages of five to 13, with at least 18 teams playing on the field every Saturday morning mid-season.
While the season doesn't officially start until May, some of the senior Red Star teams have already begun their training - and are now "stuck using half the field".
Mr Sullivan said he has been receiving message of support from the players' parents following the fire.
"They have been asking if we'll be okay, and saying they couldn't believe what happened.
"They've been asking 'who would do something like this?' We've been wondering the same."
He said Masterton District Council may assist with the irrigation process - as teams who play on council-owned land will often use the privately-owned Red Star ground if that land can't be used.
"It turns out ours is a badly-needed field in Wairarapa."
Mr Glassey said if the fires were lit deliberately, the matter would be referred to Youth Aid.